- Garlic (Allium sativum) is a food item and seasoning which has also been used for medicinal purposes.
- Garlic is said to reduce the risk of certain cancers.
- The evidence for this assumption is contradictory and not strong, being based mainly on observational studies.
- Serious adverse-effects are not on record but interactions with a range of drugs including cancer drugs might be an issue and allergic reactions are possible.
Garlic (Allium sativum) is a bulbous plant from the onion family which is widely used as food seasoning. It has also been used as a traditional medicine. Garlic is sometimes recommended for cancer-prevention based on observational population studies assessing garlic intake and risk of cancer and on studies indicating beneficial effects on processes such as activation of carcinogenic substances, cell proliferation and apoptosis (cell death). Reviews of the epidemiological evidence are contradictory due to differences in the methods used in the reviews, confounding factors and, possibly, to the nature and quality of the garlic consumed. While some reviews conclude that, for some types of cancer including gastric cancer, regular garlic intake might reduce the risk, this is based on a mixture of study types and, often, a lack of quality assessment. Only very few clinical trials exist and their results are inconclusive. Serious adverse events are not to be expected at recommended doses or normal levels of dietary intake but herb-drug interactions might occur.
Citation
Karen Pilkington, Edzard Ernst, CAM Cancer Consortium. Garlic (Allium sativum) [online document], November 14, 2018.
Document history
Fully revised and updated in November 2018 by Karen Pilkington.
Revised and updated in August 2013 by Edzard Ernst.
Summary first published in September 2011, authored by Edzard Ernst.
Description
Garlic is a bulbous plant of the Allium (onion) family, the bulb usually being composed of sections called cloves which produce a pungent odour, particularly when chopped or crushed, due to various sulfur compounds. Commonly used for culinary purposes, it is related to chives, leeks and onions and cultivated in most countries. For medicinal purposes, fresh or dried parts of the garlic bulb or the oil from the bulb are usually used.
Scientific / common name
Allium sativum L (Alliaceae/Liliaceae) is commonly referred to as garlic. Ajo is also sometimes used.
Ingredients
Alliin, diallyldisulfate, ajoen and others1. Allicin, considered to be one of the main active ingredients, and other sulfur-containing compounds are formed from alliin enzymatically when garlic is crushed or chopped1,2. It is considered that 1 mg alliin is equivalent to 0.45 mg allicin2,3. Commercial garlic preparations are often standardised on the content of sulfur-containing constituents, particularly to alliin, or on the allicin yield2.
Application and dosage
Garlic may be consumed in food as part of the normal diet usually as fresh garlic cloves added when cooking. It may also be taken as a medicinal preparation, for example, as capsules of the dried product. Doses vary widely depending on the product and indication. The following are some examples of dose ranges that have been reported:
Dried bulb: 2- 4g three times daily for upper respiratory tract infections4-6; 0.5-1.0 g daily for the prophylaxis of atherosclerosis7,8.
Fresh garlic: 4g daily1-3.
Oil: 0.03-0.12 ml three times daily2,9.
Juice of garlic (BPC 1949) 2-4 ml2,10.
Extract: 600-900mg of standardised extract (1.3% alliin content) daily in divided doses1.
The World Health Organization’s (WHO) 1999 guidelines on dose for adults are, unless otherwise prescribed, fresh garlic, 2–5 g; dried powder, 0.4–1.2 g; oil, 2–5 mg; extract, 300–1000 mg (as solid material)4.
For colorectal cancer, aged garlic extract 2.4 mL daily for 12 months as capsules has been used11,12,13, while for prostate cancer, a dose of 1 mg/kg of aqueous garlic extract for one month has been used14,15. In prevention of cancer, 200 mg synthetic allitridum/day has been used16,17 as has 400 mg aged garlic extract and 2 g garlic oil twice daily18.
History/providers
Garlic has been used medicinally in several ancient cultures. Prescribers today are mainly herbalists, naturopaths and doctors. Many consumers self-prescribe garlic supplements. Garlic is a common food and spice. It is offered as “over the counter “ (OTC) preparations (food supplements) in form of single-ingredient or multi-ingredients preparations by many providers11.
Claims of efficacy
The ESCOP Monograph (2003) recommends Allii sativi bulbus for the prophylaxis of atherosclerosis, for the treatment of elevated blood lipid levels insufficiently influenced by diet, for the improvement of the circulation in peripheral arterial vascular disease and for upper respiratory tract infections and catarrhal conditions3.
The WHO-Monograph states the that uses supported by clinical data are: as adjuvant to the dietetic management in the treatment of hyperlipidaemia, and in the prevention of atherosclerosis, age-dependent vascular changes and mild hypertension4.
In the context of cancer, it is claimed that garlic might reduce the cancer risk. Claims of efficacy in the prevention of cancer are based on in vitro and animal studies2 and the results of large-scale observational studies (see Does it work section?)
Mechanism of action
Garlic's mechanisms of action have been studied extensively. It has antibacterial, antiviral, antifungal, antihypertensive, blood glucose lowering, antithrombotic, antimutagentic and antiplatelet activities1.
Several pathways have been identified for each of which the evidence is substantial:
- Modulation of carcinogen metabolism12
- Inhibition of cell cycle progression19
- Induction of apoptosis20-25
- Histone modification12
- Inhibition of angiogenesis12
- Protection against DNA-damage26
- Inhibition of cell proliferation27-30
- Modulation of gene expression27,31
- Inhibition of tumor cell motility32
- Antioxidation33
- Modification of drug metabolising enzymes especially the family of the hepatic cytochrome P450 (CYP) enzymes2
- Immunomodulatory activity2,34
Many of the findings from animal studies support these postulated mechanisms23,28-30,33-36.
Prevalence of use
Garlic is widely used as a food and seasoning. Garlic supplements have become very popular in developed countries. Exact prevalence figures are not available. Garlic was reported to be used by approximately 10% of the Australian population in the past 12 months37. A similar prevalence was found in the USA38. Specific reasons for use were not recorded.
Legal issues
Garlic preparations are sold in most countries as food supplements, in the EU some preparation are medicinal herbal products.
Cost and expenditure
A one week supply of garlic supplements would cost between €5 and €10.
The literature on garlic (Allium sativum) as a means of reducing cancer risk is huge. Therefore, the following section is mainly based on systematic reviews and meta-analyses of the observational studies. The key characteristics of these are included in Table 1.
Systematic reviews, meta-analyses
Colorectal cancer
Four meta-analyses39-42, two ‘evidence-based’ reviews43,44 and one systematic review with meta-analysis45 assessed whether consumption of garlic was associated with risk of colorectal cancer. Four of these found no reduced risk of colorectal cancer with higher levels of garlic consumption, two found risk to be reduced and one reported that risk appeared to be increased by garlic supplements. The reason for the differences may be due to a range of factors such as the types and numbers of studies included, quality of the studies and how recently the search was conducted. In most cases, only one or two databases were searched and only four assessed quality of the studies. The quality assessments also varied. An evidence-based overview graded studies according to design and concluded that there was evidence of a protective effect from animal studies but human studies were heterogeneous43. In the second evidence-based review, results of stronger studies were assessed separately from the weaker studies44. One of the meta-analyses included only cohort studies and carried out quality assessments judging the studies to be high quality40. The systematic review with meta-analysis included cohort and case control studies and quality of the included studies was judged to be moderate to high45. Three of the four reviews which assessed quality of the evidence found no association with garlic intake.
Gastric cancer
Four meta-analyses39,46,47,48 and the evidence-based review44 assessed whether garlic consumption was associated with gastric cancer. As above, there were differences in various aspects of the methods used in carrying out these reviews. The evidence-based review concluded that there was ‘no credible evidence’ of a link between intake and gastric cancer risk44. The four meta-analyses, all based on limited searches and no quality assessment, found a reduced risk linked to garlic (or in one case linked to total Allium) intake. One meta-analysis, which included a mixture of trials and observational studies, reported a link with high, low or even any intake of garlic versus no intake46. Two meta-analyses which included cohort and case-control studies also reported a link between garlic intake and reduced cancer risk (39,48) as did a meta-analysis of case-control studies47.
Other cancers
Two meta-analyses17,42 and the evidence-based review44 considered risk of other cancers.
The evidence-based review covered prostate cancer, breast cancer, lung cancer and various other cancers. No credible evidence of a reduction in risk was found for breast, lung, or endometrial cancer, very limited evidence (1 study each) was found for prostate, oesophageal, larynx, oral, ovary, or renal cell cancer.
A more recent meta-analysis that focused only on prostate cancer but included all Allium vegetables identified a total of 6 case-control and 3 cohort studies17. Subgroup analysis of the results for garlic intake from all the studies showed a significant association with garlic intake (OR = 0.77, 95% CI 0.64-0.91). However, while confounding variables were reported, there was no specific assessment of the effect of these or the quality of the individual studies.
Another meta-analysis focused on cancers of the oral cavity, pharynx, larynx, and oesophagus42. The risk ratio (RR) for squamous cell carcinoma indicated a reduction for highest versus lowest garlic consumption (0.74 95% CI 0.57–0.95).
There are a range of possible explanations for variations in addition to differences in the methods used in the original studies, possible confounding factors and the design of the secondary studies i.e. the meta-analyses and systematic reviews and overviews. These may include factors such as differences in the nature and quality of the garlic consumed33.
Clinical trials
Few randomised controlled trials of garlic on prevention of cancer are available17,18,41,49,50,51. All but one are included in the systematic reviews and meta-analyses described above. Their key data are summarized in table 2. Collectively these studies fail to show conclusively that garlic-intake reduces the cancer risk and thus do not provide support for any positive results reported in the observational studies. One study examined a specific use for garlic: prevention of febrile neutropenia52. As with the other trials, the results were inconclusive.
Adverse effects
Garlic (Allium sativum) is generally considered to be non-toxic (1,2,53,54. Adverse effects of unknown frequency that have been documented in humans include a burning sensation in the mouth and gastrointestinal tract, bloating, abdominal pain, fullness, anorexia2,53) and malodourous breath or body odour. Facial flushing, tachycardia, profuse sweating, bronchospasms, headache and dizziness have also been reported as has an increased risk of bleeding8 and with topical use, burn and contact dermatitis especially in children55.The allergenic potential of garlic is well recognized, and the allergens have been identified as diallyl disulfide, allylpropyl sulfide and allicin2,5. However, allergic reactions are rare3. Preclinical data on chronic toxicity are conflicting2,8. Genotoxicity studies using the micronucleus test have reported both positive and negative findings2. No evidence of mutagenicity has been reported when assessed using the Ames and Ree assay2. No conventional genotoxicity, carcinogenicity and reproduction toxicity studies are available.
Contraindications
Known allergy to Allium species. Garlic consumption should be avoided 7 days before surgery because of the post-operative bleeding risk2. Concomitant use with saquinavir is contraindicated because of the risks of decrease in plasma concentration, loss of virological response and possible resistance to one or more components of the antiretroviral regime53.
Interactions
Garlic preparations should be used with caution in patients taking oral anticoagulation therapy and/or anti-platelet therapy because they may increase bleeding times. A potential interaction between garlic and warfarin has been documented2,56. The results of two clinical trials suggest that dietary garlic consumption does not affect platelet function57,58. No relevant data are available regarding the potentiating effect of antiplatelet drugs (ASA, clopidogrel etc.) when co-administered with garlic.
In vitro, extracts of fresh garlic, garlic oil and freeze dried garlic exhibited an inhibitory effect on cytochrome P450 2C9*1, 2C19, 3A4, 3A5 and 3A7 mediated metabolism of a marker substrate59. The activity of 2D6 mediated-metabolism was generally unaffected by garlic. Extracts of the fresh garlic stimulated CYP2C9*2 metabolism of the marker substrate60,61,62. However, in patients carrying the CYP3A5*1A allele, garlic could affect the clearance of docetaxel, leading to higher toxicity61. In immortalised human hepatocytes (Fa2N-4 cells) exposure of hepatocytes to garlic extract (0-200 μg/ml) may reduce the expression and activity of CYP2C9 with no detectible effects on CYP3A463. Pharmacokinetics possibly affected are e.g. cyclophosphamide, diclofenac, haloperidol, ibuprofen, naproxen, paclitaxel, piroxicam, and tamoxifen)63. In observational studies slight changes were found in CYP1A2 levels (increase) and CYP2E1 activity (decrease) (pharmacokinetics possibly affected: e.g. ondansetron, etoposide)64.
An increase has been noted in the expression of duodenal P-glycoprotein after the ingestion of garlic extracts65. This interaction is thought to be the most probable mechanism for the known impact that garlic supplements exert on the first-pass metabolism of HIV protease inhibitors53,54,66.
Finally, in observational studies alterations in the activity of the phase II biotransformation enzymes UDP glucuronosyltransferase and glutathion-S-transferase have been observed after the ingestion of garlic extracts64.
Quality issues
Garlic preparations should adhere to GAP (Good Agricultural Practices), GMP (Good Manufacturing Practices) and, in Europe, to the European guidelines “Quality of Herbal Medicinal products”.
Warning
Insufficient information exists for garlic use beyond amounts consumed as part of the daily diet during pregnancy and lactation. There are only few clinical studies during pregnancy and lactation. However, there are not experimental or clinical reports on adverse effects during pregnancy or lactation 2. There are only few clinical studies during pregnancy and lactation. However, there are not experimental or clinical reports on adverse effects during pregnancy or lactation2. In view of this, doses of garlic greatly exceeding amounts used in foods should not be taken during pregnancy and lactation2.
Other problems
Overdose may cause nausea and vomiting.
- Ernst E, Pittler MH, Wider B, Boddy K. The Desktop Guide to Complementary and Alternative Medicine, 2nd edition. Edinburgh: Elsevier Mosby, 2006.
- Barnes J, Anderson LA, Phillipson DJ. Herbal Medicines. London: Pharmaceutical Press. 2007;279-289.
- European Scientific Cooperative of Phytotherapy (ESCOP). Monographs on the Medicinal uses of plant drugs, 2nd Edition. Stuttgart: Thieme Verlag, 2003. Monograph: Allii sativi bulbus.
- WHO. Monograph on selected medicinal plants, Vol 1. Geneva: WHO. 1999. Available online, accessed November 2017.
- Papageorgiou C, et al. Allergic contact dermatitis to garlic (Allium sativum L.) Identification of the allergens: The role of mono-, di-, and trisulfides present in garlic. Arch Dermatol Res 1983; 275:229-234.
- Symposium on the chemistry, pharmacology and medicinal applications of garlic. Cardiol Pract 7, 1-15. 1989.
- Schilcher H, Kammerer S, Wegener T. Leitfaden Phytotherapie. Urban & Fischer Verlag/ Elsevier GmbH, München. 3rd Edition. 2007;151-152.
- Natural Medicines Comprehensive Database. Garlic [online monograph]. Available at , accessed November 2017.
- Bradley P. British Herbal Compendium. Vol. 1 Bournemouth: British Herbal Medicine Association. 1992.
- British Pharmaceutical Codex 1949: London: Pharmaceutical Press. 1949.
- Barnes J, Anderson LA, Phillipson DJ. Herbal Medicines. 2nd ed. London: Pharmaceutical Press. 2002.
- Antony ML, Singh SV. Molecular mechanisms and targets of cancer chemoprevention by garlic-derived bioactive compound diallyl trisulfide. Indian J Exp Biol 2011; 49(11):805-816.
- Tanaka S, Haruma K, Yoshihara M, Kajiyama G, Kira K, Amagase H, Chayama K. Aged garlic extract has potential suppressive effect on colorectal adenomas in humans. J Nutr. 2006;136:S821–26.
- Li L, Sun T, Tian J, Yang K, Yi K, Zhang P. Garlic in clinical practice: an evidence-based overview. Critical reviews in food science and nutrition. 2013;53(7):670-81.
- Durak I, Yilmaz E, Devrim E, et al. Consumption of aqueous garlic extract leads to significant improvement in patients with benign prostate hyperplasia and prostate cancer. Nutr Res 2003;23:199-204.
- Li H, Li H-Q, Wang Y, Xu H-X, Fan W-T, Want M-L et al. An intervention study to prevent gastric cancer by micro-selenium and large dose of allitridum. Chinese Med J 2004; 117(8):1155-1160.
- Zhou XF, Ding ZS, Liu NB. Allium vegetables and risk of prostate cancer: evidence from 132,192 subjects. Asian Pac J Cancer Prev 2013;14(7):4131-4.
- You WC, Brown LM, Zhang L, Jin M-L, Chang Y-S, et al. Randomized double-blind factorial trial of three treatments to reduce the prevalence of precancerous gastric lesions. J Natl Cancer Inst 2006; 98:974-983.
- Viry E, Anwar A, Kirsch G, Jacob C, Diederich M, Bagrel D. Antiproliferative effect of natural tetrasulfides in human breast cancer cells is mediated through the inhibition of the cell division cycle 25 phosphatases. Int J Oncol 2011; 38(4):1103-1111.
- Kim SH, Bommareddy A, Singh SV. Garlic constituent diallyl trisulfide suppresses x-linked inhibitor of apoptosis protein in prostate cancer cells in culture and in vivo. Cancer Prev Res (Phila) 2011; 4(6):897-906.
- Lee JE, Lee RA, Kim KH, Lee JH. Induction of apoptosis with diallyl disulfide in AGS gastric cancer cell line. J Korean Surg Soc 2011; 81(2):85-95.
- Lee Y, Kim H, Lee J, Kim K. Anticancer activity of S-allylmercapto-L-cysteine on implanted tumor of human gastric cancer cell. Biol Pharm Bull 2011; 34(5):677-681.
- Li W, Tian H, Li L, Li S, Yue W, Chen Z et al. Diallyl trisulfide induces apoptosis and inhibits proliferation of A549 cells in vitro and in vivo. Acta Biochim Biophys Sin (Shanghai) 2012; 44(7):577-583.
- Yu CS, Huang AC, Lai KC, Huang YP, Lin MW, Yang JS et al. Diallyl trisulfide induces apoptosis in human primary colorectal cancer cells. Oncol Rep 2012; 28(3):949-954.
- Zhang W, Ha M, Gong Y, Xu Y, Dong N, Yuan Y. Allicin induces apoptosis in gastric cancer cells through activation of both extrinsic and intrinsic pathways. Oncol Rep 2010; 24(6):1585-1592.
- Chang HS, Endoh D, Ishida Y, Takahashi H, Ozawa S, Hayashi M et al. Radioprotective effect of alk(en)yl thiosulfates derived from allium vegetables against DNA damage caused by X-ray irradiation in cultured cells: antiradiation potential of onions and garlic. ScientificWorldJournal 2012; 2012:846750-doi: 10.1100/2012/846750.
- Huang YS, Xie N, Su Q, Su J, Huang C, Liao QJ. Diallyl disulfide inhibits the proliferation of HT-29 human colon cancer cells by inducing differentially expressed genes. Mol Med Rep 2011; 4(3):553-559.
- Kaneko T, Shimpo K, Chihara T, Beppu H, Tomatsu A, Shinzato M et al. Inhibition of ENNG-induced pyloric stomach and small intestinal carcinogenesis in mice by high temperature- and pressure-treated garlic. Asian Pac J Cancer Prev 2012; 13(5):1983-1988.
- Liang D, Qin Y, Zhao W, Zhai X, Guo Z, et al. S-allylmercaptocysteine effectively inhibits the proliferation of colorectal cancer cells under in vitro and in vivo conditions. Cancer Lett 2011; 310(1):69-76.
- Wu PP, Liu KC, Huang WW, Chueh FS, Ko YC, Chiu TH et al. Diallyl trisulfide (DATS) inhibits mouse colon tumor in mouse CT-26 cells allograft model in vivo. Phytomedicine 2011; 18(8-9):672-676.
- Lai KC, Kuo CL, Ho HC, Yang JS, Ma CY, Lu HF et al. Diallyl sulfide, diallyl disulfide and diallyl trisulfide affect drug resistant gene expression in colo 205 human colon cancer cells in vitro and in vivo. Phytomedicine 2012; 19(7):625-630.
- Park HS, Kim GY, Choi IW, Kim ND, Hwang HJ, Choi YW et al. Inhibition of matrix metalloproteinase activities and tightening of tight junctions by diallyl disulfide in AGS human gastric carcinoma cells. J Food Sci 2011; 76(4):T105-T111.
- Shirzad H, Taji F, Rafieian-Kopaei M. Correlation between antioxidant activity of garlic extracts and WEHI-164 fibrosarcoma tumor growth in BALB/c mice. J Med Food 2011; 14(9):969-974.
- Wang X, Jiao F, Wang QW, Wang J, Yang K, Hu RR. Aged black garlic extract induces inhibition of gastric cancer cell growth in vitro and in vivo. Mol Med Rep 2012; 5(1):66-72.
- Bianchini F, Vainio H. Allium vegetables and organosulfur compounds: do they help prevent cancer? Envir Health Persp 2001; 109(9):893-902.
- Appel E, Rabinkov A, Neeman M, Kohen F, Mirelman D. Conjugates of daidzein-alliinase as a targeted pro-drug enzyme system against ovarian carcinoma. J Drug Target 2011; 19(5):326-335.
- Zhang AL, Story DF, Lin V, Vitetta L, Xue CC. A population survey on the use of 24 common medicinal herbs in Australia. Pharmacoepidemiol Drug Saf. 2008 Oct;17(10):1006-13.
- Barnes PM, Bloom B, Nahin RL. Complementary and alternative medicine use among adults and children: United States, 2007. Natl Health Stat Report. 2008 Dec 10;(12):1-23.
- Fleischauer AT, Poole C, Arab L. Garlic consumption and cancer prevention: meta-analyses of colorectal and stomach cancers. Am J Clin Nutr 2000; 72:1047-1052.
- Hu JY, Hu YW, Zhou JJ, Zhang MW, Li D, Zheng S. Consumption of garlic and risk of colorectal cancer: an updated meta-analysis of prospective studies. World J Gastroenterol. 2014 Nov 7;20(41):15413-22.
- Turati F, Guercio V, Pelucchi C, La Vecchia C, Galeone C. Colorectal cancer and adenomatous polyps in relation to allium vegetables intake: a meta-analysis of observational studies. Mol Nutr Food Res. 2014 Sep;58(9):1907-14.
- Guercio V, Turati F, La Vecchia C, Galeone C, Tavani A. Allium vegetables and upper aerodigestive tract cancers: a meta-analysis of observational studies. Mol Nutr Food Res. 2016 Jan;60(1):212-22.
- Ngo SN, Williams DB, Cobiac L, Head RJ. Does garlic reduce risk of colorectal cancer? A systematic review. J Nutr 2007;137:2264-9.
- Kim JY, Kwon O. Garlic intake and cancer risk: an analysis using Food and Drug Adminstration's evidence-based review system for the scientific evaluation of health claims. Am J Clin Nutr 2009; 89:257-264.
- Chiavarini M, Minelli L, Fabiani R. Garlic consumption and colorectal cancer risk in man: a systematic review and meta-analysis. Public Health Nutr. 2016 Feb;19(2):308-17
- Kodali RT, Eslick GD. Meta-analysis: Does garlic intake reduce risk of gastric cancer? Nutr Cancer. 2015;67(1):1-11
- Turati F, Pelucchi C, Guercio V, La Vecchia C, Galeone C. Allium vegetable intake and gastric cancer: a case-control study and meta-analysis. Mol Nutr Food Res. 2015 Jan;59(1):171-9.
- Zhou Y, Zhuang W, Liu GJ, Wu TX, Wu XT. Consumption of large amounts of Allium vegetables reduces risk for gastric cancer in a meta-analysis. Gastroenterology 2011; 141(1):80-89.
- Tanaka S, Haruma K, Masaki K, Nagata S, Kitadai Y, Manabe N et al. Effects of aged garlic extract (AGE) on colorectal adenomas: a double-blinded study. Hiroshima J Med Sci 2004; 53(3-4):39-45.
- Zhu B, Zou L, Qi L, Zhong R, Miao X. Allium vegetables and garlic supplements do not reduce risk of colorectal cancer, based on meta-analysis of prospective studies. Clin Gastroenterol Hepatol. 2014 Dec;12(12):1991-2001.
- Ma JL, Zhang L, Brown LM, Li JY, Shen L, Pan KF, Liu WD, Hu Y, Han ZX, Crystal-Mansour S, Pee D, Blot WJ, Fraumeni JF Jr, You WC, Gail MH. Fifteen-year effects of Helicobacter pylori, garlic, and vitamin treatments on gastric cancer incidence and mortality. J Natl Cancer Inst. 2012 Mar 21;104(6):488-92
- Gatt ME, Strahilevitz J, Sharon N, Lavie D, Goldschmidt N, Kalish Y, et al. A Randomized Controlled Study to Determine the Efficacy of Garlic Compounds in Patients With Hematological Malignancies at Risk for Chemotherapy-Related Febrile Neutropenia. Integrative cancer therapies. 2015;14(5):428-35.
- Piscitelli SC, Burstein AH, Welden N, Gallicano KD, Falloon J. The effect of garlic supplements on the pharmacokinetics of saquinavir. Clin Infect Dis 2002; 34(2):234-238.
- Berginc K, Milisav I, Kristl A. Garlic flavonoids and organosulfur compounds: impact on the hepatic pharmacokinetics of saquinavir and darunavir. Drug Metab Pharmacokinet 2010; 25(6):521-530.
- Shamseer L, Charrois T and Vohra S. Complementary, Holistic, and Integrative Medicine: Garlic. Pediatr Rev 2006;27:77-80.
- Ishikawa H, Saeki T, Otani T, Suzuki T, Shimozuma K, Nishino H et al. Aged garlic extract prevents a decline of NK cell number and activity in patients with advanced cancer. J Nutr 2006; 136:816S-823S.
- Beckert BW, Concannon MJ, Henry SL, Smith DS, Puckett CL. The effect of herbal medicines on platelet function: an in vivo experiment and review of the literature. Plast Reconstr Surg 2007;120:2044-50.
- Scharbert G, Kalb ML, Duris M, Marschalek C, Kozek-Langenecker SA. Garlic at dietary doses does not impair platelet function. Anesth Analg. 2007;105:1214-8.
- Ho BE, Shen DD, McCune JS, Bui T, Risler L, Yang Z et al. Effects of Garlic on Cytochromes P450 2C9- and 3A4-Mediated Drug Metabolism in Human Hepatocytes. Sci Pharm 2010; 78(3):473-481.
- Foster BC, Foster MS, Vandenhoek S, Krantis A, Budzinski JW, Arnason JT et al. An in vitro evaluation of human cytochrome P450 3A4 and P-glycoprotein inhibition by garlic. J Pharm Pharm Sci 2001;4:176-84.
- Cox MC, Low J, Lee J, Walshe J, Denduluri N, Berman A et al. Influence of garlic (Allium sativum) on the pharmacokinetics of docetaxel. Clin Cancer Res 2006; 12(15):4636-4640.
- Greenblatt DJ, Leigh-Pemberton RA, von Moltke LL. In vitro interactions of water-soluble garlic components with human cytochromes p450. J Nutr 2006; 136(3 Suppl):806S-809S.
- Ho BE, Shen DD, McCune JS, Bui T, Risler L, Yang Z et al. Effects of Garlic on Cytochromes P450 2C9- and 3A4-Mediated Drug Metabolism in Human Hepatocytes. Sci Pharm. 2010, 78(3):473-481
- Le Bon AM, Vernevaut MF, Guenot L, Kahane R, Auger J, Arnault I et al. Effects of garlic powders with varying alliin contents on hepatic drug metabolizing enzymes in rats. J Agric Food Chem 2003; 51(26):7617-1623.
- Hajda J, Rentsch KM, Gubler C, Steinert H, Stieger B, Fattinger K. Garlic extract induces intestinal P-glycoprotein, but exhibits no effect on intestinal and hepatic CYP3A4 in humans. Eur J Pharm Sci 2010; 41(45):729-735.
- Berginc K, Trdan T, Trontelj J, Kristl A. HIV protease inhibitors: garlic supplements and first-pass intestinal metabolism impact on the therapeutic efficacy. Biopharm Drug Dispos 2010; 31(8-9):495-505.