Curcumin is the major constituent and active component of the turmeric plant (Curcuma longa). Turmeric is the bright-yellow spice made from the rhizome of the turmeric plant. Medicinally, curcumin is used as a supplement. In cancer care, it has been investigated for reducing adverse effects of chemo- or radiotherapy, and for its anticancer properties.
Oral mucositis
Across three systematic reviews, curcumin showed consistent evidence of reducing the severity of oral mucositis.
Positive findings were also reported for reducing oral pain, delay mucositis onset, and reduce treatment-related weight loss.
However, confidence in these findings is limited because most underlying trials were small, heterogeneous, and at moderate to high risk of bias.
Radiation dermatitis
Evidence from five systematic reviews suggests that curcumin may reduce the severity of radiation dermatitis; however, findings are inconsistent across reviews.
One SR found evidence for reducing radiation dermatitis severity, severe dermatitis incidence, and pain associated with skin toxicity.
Confidence in the evidence remains limited by substantial heterogeneity and the generally high risk of bias of the included RCTs.
Anticancer treatment
Despite extensive preclinical research, the findings of three SRs do not confirm reliable improvements in survival, progression-free survival, or disease-free outcomes with curcumin/turmeric supplementation. Clinical evidence for direct antitumor activity in patients remains limited and inconsistent.
Findings were based on few studies with small sample sizes and concerns about methodological quality, which suggests very low to low confidence in the findings.
Safety
Curcumin is generally recognized as safe by the US Food and Drug Administration (FDA) and has been used safely at doses up to 12g daily for several months. Few adverse events, mainly digestive complaints, have been reported.
Caution has been advised for concomitant use with certain medications including tamoxifen.
Description
Curcumin is derived from the rhizome of the plant turmeric (Curcuma longa). It is one of the main active components of turmeric. Turmeric belongs to the ginger family or Zingiberaceae. Originally from South Asia, turmeric now grows in tropical areas across the world.
Turmeric is the major ingredient of curry powder, a bright yellow-orange food colouring agent (E100), and used as colourant of paper, clothes and cosmetics. (Goel 2020; Jurenka 2009; Govindarajan 1980).
Ingredients and quality issues
Turmeric (Curcuma longa) contains:
- 3-5% curcuminoids with main component curcumin (diferuloylmethane), demethoxycurcumin and bisdemethoxycurcumin,
- 2-7% volatile oils composed of monoterpenes and sesquiterpenes,
- 30-40% starch and other polysaccharides (glycans). (Jurenka 2009; WHO 1999)
Curcuminoids contain approximately 77% curcumin, although commercial preparations may standardize to a higher curcumin content (Adiwidjaja 2017).
Curcumin has low oral bioavailability due primarily to low water solubility, and to a lesser extent poor intestinal permeability and extensive first-pass metabolism (Adiwidjaja 2017). Bioavailability-enhanced products are available but vary widely in effectiveness. (Jamwal 2018).
To improve bioavailability, a variety of approaches have been used and studied including curcumin-piperine complexes, curcumin nanoparticles, cyclodextrin inclusions, curcumin liposomes, and curcumin phospholipid complexes (Jamwal 2018).
An evaluation of turmeric dietary supplement quality in the United States market found that most turmeric products contained curcuminoid content within 80% of advertised, but curcuminoid composition was suggestive of possible use of unlabelled synthetic curcumin in some products. Lead was found in only one product, and residues of toxic class 1 or 2 solvents were within US Pharmacopeia-specified limits. (Skiba 2018)
Alleged indications
Curcumin has been used medicinally in traditional Ayurvedic medicine and traditional Chinese medicine for a variety of illnesses, including skin diseases, infections, digestive complaints, meteorism, nausea and vomiting, peptic ulcer, diseases of the gall bladder and liver, inflammatory diseases (Singh 2007). The best evidence for its use is in inflammatory and metabolic conditions such as arthritis, inflammatory bowel disease, metabolic syndrome, and hyperlipidemia. (Hewlings 2017,Kuttan 1985).
In the context of cancer care, curcumin has been claimed to have broad anti-cancer effects including suppression of cancer initiation, progression, and metastases of various cancers, and apoptotic and antiproliferative effects. Furthermore, it has been used to protect from skin-related adverse events of radio- and chemotherapy. (Shanmugm 2015; Devassy 2015)
Application and dosage
Turmeric is used in various topical formulations, including as a mouthwash, gel, cream, and tonic, as well as orally.
Oral doses of curcumin vary based on formulation and relative curcumin content (e.g. turmeric powder contains only 3-5% curcumin, TheracurminTM contains 10% curcumin). Turmeric powder has been studied at a dose of 15g daily (Ghalaut 2012).
Unformulated curcumin has been studied in doses up to 8g daily for 3 months without significant AEs (Li 2014), and studies in in cancer using unformulated curcumin orally have used 1.4-6g daily (Ryan 2013; Choi 2019). Dosing of bioavailability-enhanced formulas is typically lower, ranging from 80mg-4g (Delavarian 2019).
Mechanisms of action
Curcumin is a bioactive compound that acts on multiple signalling pathways in the body. It has antioxidant properties, helping to neutralise reactive oxygen species (ROS), and anti-inflammatory effects through the inhibition of enzymes involved in ROS production. Curcumin has also been shown to inhibit cell proliferation and promote apoptosis (programmed cell death) (Devassy 2015).
Experimental studies suggest that these anticancer effects are mediated through several mechanisms, including the inhibition of proteins and enzymes involved in tumour growth and inflammation, such as PKC, EGFR, iNOS, and COX-2. Curcumin has also been shown to inhibit MMP-9 and VEGF, which are involved in tumour invasion and angiogenesis (formation of new blood vessels) (Lin 2001; Lu 2010).
In addition, curcumin can modulate several key signalling pathways associated with cancer development and progression, including NF-κB, MAPK, Notch-1, Nrf2, Wnt/β-catenin, and JAK/STAT pathways (Devassy 2015).
Curcumin may also enhance the effectiveness of chemotherapy and radiotherapy by influencing pathways involved in tumour growth, survival, inflammation, and treatment resistance. These include NF-κB, STAT-3, COX-2, Akt, growth factor receptors, and multidrug-resistance proteins (Goel 2010).
Curcumin’s radioprotective effects have mainly been attributed to its antioxidant and anti-inflammatory properties, which might mitigate radiation-induced oxidative stress and DNA damage (Shanmugm 2015).
Legal aspects
Curcumin is widely as a food supplement across the EU under food law regulations as a food additive and natural orange-yellow food colouring (E 100). It has been evaluated by the EMA's Committee on Herbal Medicinal Products as a herbal medicinal product (Curcumae longae rhizoma) and is authorized in certain EU countries as a traditional herbal medicine to treat digestive complaints like mild indigestion or biliary disturbances.
This evidence summary is based on systematic reviews (SRs) published between January 2021 and 2026, which were retrieved through systematic literature searches. It assesses whether curcumin improves various cancer-related symptoms and outcomes:
CAM Cancer appraised the quality of the SRs with the AMSTAR2 tool and only included SRs of moderate or high quality, while SRs of low or critically low quality were excluded. The full description of the included studies can be viewed in the evidence tables.
Curcumin and curcuminoids are generally recognized as safe (GRAS) by the FDA (Hewlings 2017). Clinical trials including several phase I studies using curcumin in patients with advanced pancreatic cancer (Dhillon 2008; Kanai 2013; Kanai 2011; Epelbaum 2010), have demonstrated good tolerability and safety in doses up to 8g daily taken for a period of up to 18 months (Bayet-Robert 2010; Cheng 2001; Hewlings 2017), and in high doses of up to 12g for 3 months (Jurenka 2009; Lao 2006).
Adverse effects / toxicity
Possible adverse effects include gastro-intestinal side effects such as diarrhoea and nausea (Hewlings 2017; Epelbaum 2010), and a potential for allergic dermatitis related to topical administration (Goel 2008).
Serious adverse events have not been reported.
Contraindications
There are no known absolute contraindications to curcumin supplementation. There is insufficient data for use in pregnancy and lactation.
Interactions
CYP enzymes
Preclinical studies have reported alterations in various CYP P450 enzyme function with curcumin, which could lead to interactions with medications (Adiwidjaja 2018). Curcumin has been reported to inhibit CYP1A2 function and enhance CYP2A6 activity in healthy, male Chinese volunteers (Chen 2010). Two studies have found no effect of curcumin on CYP 3A4 activity (Fabiani 2018; Al-Jenoobi 2015). A randomized, placebo-controlled six-way crossover study in eight healthy volunteers found that short-term administration of 4g curcuminoids with piperine had no impact on pharmacokinetics of midazolam (CYP3A probe), flurbiprofen (CYP2C9 probe) or paracetamol (UGT and SULT probe) (Volak 2013) Therefore, curcumoinoids with piperine were deemed unlikely to result in an interaction involving CYP 3A, CYP2C9 or paracetamol conjugation enzymes. Curcumin may inhibit intestinal ABCB1 transporter, and preclinical data has demonstrated similar results for ABCB2 (Adiwidjaja 2018).
Tamoxifen (SERM)
Curcumin may reduce effectiveness of tamoxifen by altering the metabolism of the prodrug tamoxifen to active endoxifen (Hussaarts 2019). A dose of 1200mg curcumin with 10mg piperine administered 3x daily with tamoxifen reduced endoxifen area under the curve 12.4% (p=0.002) compared to tamoxifen alone. This is consistent with another study that found inhibition of CYP2D6 with curcumin (Al-Jenoobi 2015), which is the enzyme responsible for conversion of tamoxifen to endoxifen.
Antithrombotic agents
Preclinical data has suggested antiplatelet and anticoagulant effects of curcumin and thus possible additive effects with anticoagulant medications (Kim 2012; Goel 2008). However, human studies have failed to demonstrate a clinically or significantly meaningful effect of curcumin with antiplatelet and anticoagulant medications including acetylsalicylic acid, tipopidine, clopidogrel, warfarin, and dabigatran (Hu 2018; Fung 2017). Caution is warranted until more is known.
Systematic reviews of curcumin as anticancer treatment
Systematic reviews of curcumin for oral mucositis
Systematic reviews of curcumin for radiation dermatitis
Adiwidjaja J, McLachlan AJ, Boddy AV. Curcumin as a clinically-promising anti-cancer agent: pharmacokinetics and drug interactions. Expert Opin Drug Metab Toxicol. 2017;13(9):953-972.
Al-Jenoobi FI, Al-Thukair AA, Alam MA, et al. Effect of Curcuma longa on CYP2D6- and CYP3A4-mediated metabolism of dextromethorphan in human liver microsomes and healthy human subjects. Eur J Drug Metab Pharmacokinet. 2015;40(1):61-66.
Bayet-Robert M, Kwiatkowski F, Leheurteur M, Gachon F, Planchat E, Abrial C, et al. Phase I dose escalation trial of docetaxel plus curcumin in patients with advanced and metastatic breast cancer. Cancer Biol Ther 2010 Jan;9(1):8-14.
Berkovitz, S., Collaço, N., Dolakova, K., & Hughes, J. (2026). A systematic review of turmeric/curcumin for prevention and treatment of oral mucositis due to radiotherapy and/or chemotherapy for head and neck cancer. Journal of Integrative and Complementary Medicine. Advance online publication. https://doi.org/10.1177/27683605261426992
Chen Y, Liu W, Chen B, Fan L, Han Y et al. Plant polyphenol curcumin significantly affects CYP1A2 and CYP2A6 activity in healthy, male Chinese volunteers. Ann Pharmacother 2010;44:1038-45.
Choi YH, Han DH, Kim S-W, et al. A randomized, double-blind, placebo-controlled trial to evaluate the role of curcumin in prostate cancer patients with intermittent androgen deprivation. Prostate. 2019;79(6):614-621.
Delavarian Z, Pakfetrat A, Ghazi A, et al. Oral administration of nanomicelle curcumin in the prevention of radiotherapy-induced mucositis in head and neck cancers. Spec Care Dentist. 2019;39(2):166-172.
Devassy JG, Nwachukwu ID, Jones PJH. Curcumin and cancer: barriers to obtaining a health claim. Nutrition reviews. 2015;73(3):155-165.
de Waure C, Bertola C, Baccarini G, Chiavarini M, Mancuso C. Exploring the Contribution of Curcumin to Cancer Therapy: A Systematic Review of Randomized Controlled Trials. Pharmaceutics. 2023;15(4):1275. doi:10.3390/pharmaceutics15041275.Cheng AL, Hsu CH, Lin JK, Hsu MM, Ho YF, Shen TS, et al. Phase I clinical trial of curcumin, a chemopreventive agent, in patients with high-risk or pre-malignant lesions. Anticancer Res 2001 Jul;21(4B):2895-900.Dhillon N, Aggarwal BB, Newman RA, et al. Phase II trial of curcumin in patients with advanced pancreatic cancer. Clin Cancer Res. 2008;14(14):4491-4499.
Epelbaum R, Schaffer M, Vizel B, Badmaev V, Bar-Sela G. Curcumin and gemcitabine in patients with advanced pancreatic cancer. Nutrition and cancer. 2010;62(8):1137-1141.
Fabiani A, Morosetti C, Filosa A, et al. Effect on prostatic specific antigen by a short time treatment with a Curcuma extract: A real life experience and implications for prostate biopsy. Arch Ital Urol Androl. 2018;90(2):107-111.
Fung FY, Wong WH, Ang SK, et al. A randomized, double-blind, placebo- controlled study on the anti-haemostatic effects of Curcuma longa, Angelica sinensis and Panax ginseng. Phytomedicine : international journal of phytotherapy and phytopharmacology. 2017;32:88-96.
Ghalaut VS, Sangwan L, Dahiya K, Ghalaut PS, Dhankhar R, Saharan R. Effect of imatinib therapy with and without turmeric powder on nitric oxide levels in chronic myeloid leukemia. J Oncol Pharm Pract. 2012;18(2):186-190.
Goel A, Aggarwal BB. Curcumin, the golden spice from Indian saffron, is a chemosensitizer and radiosensitizer for tumors and chemoprotector and radioprotector for normal organs. Nutr Cancer 2010;62(7):919-30.
Goel A, Kunnumakkara AB, Aggarwal BB. Curcumin as "Curecumin": from kitchen to clinic. Biochem Pharmacol 2008 Feb 15;75(4):787-809.
Govindarajan, V., CRC critical review: turmeric - Chemistry, Technology, and Quality. Food science and nutrition, 1980. 12(3): p. 199-301.
Gutsche, L. C., Drefer, J., & Hüber, J. (2025). Curcumin as a complementary treatment in oncological therapy: A systematic review. European Journal of Clinical Pharmacology, 81, 1-33. https://doi.org/10.1007/s00228-024-03764-9Hewlings SJ, Kalman DS. Curcumin: A Review of Its' Effects on Human Health. Foods. 2017;6(10):92.
Howells LM, Iwuji COO, Irving GRB, et al. Curcumin Combined with FOLFOX Chemotherapy Is Safe and Tolerable in Patients with Metastatic Colorectal Cancer in a Randomized Phase IIa Trial. The Journal of nutrition. 2019;149(7):1133-1139.
Hu S, Belcaro G, Dugall M, et al. Interaction study between antiplatelet agents, anticoagulants, thyroid replacement therapy and a bioavailable formulation of curcumin (Meriva®). European review for medical and pharmacological sciences. 2018;22(15):5042-5046.
Hussaarts KGAM, Hurkmans DP, Oomen-de Hoop E, et al. Impact of Curcumin (with or without Piperine) on the Pharmacokinetics of Tamoxifen. Cancers. 2019;11(3):403.
Jamwal R. Bioavailable curcumin formulations: A review of pharmacokinetic studies in healthy volunteers. J Integr Med. 2018;16(6):367-374.
Jurenka JS. Anti-inflammatory properties of curcumin, a major constituent of Curcuma longa: a review of preclinical and clinical research. Altern Med Rev 2009 Jun;14(2):141-53.
Kanai M, Otsuka Y, Otsuka K, et al. A phase I study investigating the safety and pharmacokinetics of highly bioavailable curcumin (Theracurmin) in cancer patients. Cancer Chemother Pharmacol. 2013;71(6):1521-1530.
Kanai M, Yoshimura K, Asada M, et al. A phase I/II study of gemcitabine-based chemotherapy plus curcumin for patients with gemcitabine-resistant pancreatic cancer. Cancer Chemother Pharmacol. 2011;68(1):157-164.
Kim D-C, Ku S-K, Bae J-S. Anticoagulant activities of curcumin and its derivative. BMB Rep. 2012;45(4):221-226.
Kuttan R, Bhanumathy P, Nirmala K, George MC. Potential anticancer activity of turmeric (Curcuma longa). Cancer Lett 1985 Nov;29(2):197-202.
Lao CD, Ruffin MT, Normolle D, Heath DD, Murray SI, Bailey JM, et al. Dose escalation of a curcuminoid formulation. BMC Complement Altern Med 2006;6:10.
Li, Y. and T. Zhang, Targeting cancer stem cells by curcumin and clinical applications. Cancer Lett, 2014. 346(2): p. 197-205.
Limbrunner, J., Doerfer, J., Pietschmann, K., Buente, J., Scharpenberg, M., & Huebner, J. (2025). The influence of antioxidant supplementation on adverse effects and tumor interaction during radiotherapy: A systematic review. Clinical and Experimental Medicine, 25, 258. https://doi.org/10.1007/s10238-025-01804-x
Lu B, Yu L, Xu L, Chen H, Zhang L, Zeng Y. The effects of radix curcumae extract on expressions of VEGF, COX-2 and PCNA in gastric mucosa of rats fed with MNNG. Curr Pharm Biotechnol 2010 Apr;11(3):313-7.
Rao S, Hegde SK, Baliga-Rao MP, et al. Sandalwood Oil and Turmeric-Based Cream Prevents Ionizing Radiation-Induced Dermatitis in Breast Cancer Patients: Clinical Study. Medicines (Basel, Switzerland). 2017;4(3):43.
Robijns, J., Becherini, C., Caini, S., Ryan Wolf, J., van den Hurk, C., Beveridge, M., Lam, H., Bonomo, P., Chow, E., & Behroozian, T. (2023). Natural and miscellaneous agents for the prevention of acute radiation dermatitis: A systematic review and meta-analysis. Supportive Care in Cancer, 31, Article 195. https://doi.org/10.1007/s00520-023-07656-zLin JK, Lin-Shiau SY. Mechanisms of cancer chemoprevention by curcumin. Proc Natl Sci Counc Repub China B 2001 Apr;25(2):59-66.
Ryan JL, Heckler CE, Ling M, et al. Curcumin for radiation dermatitis: a randomized, double-blind, placebo-controlled clinical trial of thirty breast cancer patients. Radiat Res. 2013;180(1):34-43.
Ryan Wolf J, Heckler CE, Guido JJ, et al. Oral curcumin for radiation dermatitis: a URCC NCORP study of 686 breast cancer patients. Supportive care in cancer : official journal of the Multinational Association of Supportive Care in Cancer. 2018;26(5):1543-1552.
Shanmugam MK, Rane G, Kanchi MM, et al. The multifaceted role of curcumin in cancer prevention and treatment. Molecules (Basel, Switzerland). 2015;20(2):2728-2769.
Singh S. From exotic spice to modern drug? Cell 2007 Sep 7;130(5):765-8.
Skiba MB, Luis PB, Alfafara C, Billheimer D, Schneider C, Funk JL. Curcuminoid Content and Safety-Related Markers of Quality of Turmeric Dietary Supplements Sold in an Urban Retail Marketplace in the United States. Molecular nutrition & food research. 2018:e1800143-e1800143.
Vasconcelos, S. C. C. M. e., Guerra, E. N. S., de Menêses, A. G., dos Reis, P. E. D., & Ferreira, E. B. (2023). Effects of oral supplementation to manage radiation dermatitis in cancer patients: A systematic review. Supportive Care in Cancer, 31, 240. https://doi.org/10.1007/s00520-023-07685-8
Volak LP, Hanley MJ, Masse G, et al. Effect of a herbal extract containing curcumin and piperine on midazolam, flurbiprofen and paracetamol (acetaminophen) pharmacokinetics in healthy volunteers. British journal of clinical pharmacology. 2013;75(2):450-462.
WHO, WHO Monograph Rhizoma curcumae longae. In WHO monographs on selected medicinal plants. Genf 1999. 1(Rhizoma Curcumae Longae): p. 115-124.
Zhan, L., Qia, M., Cha, Y., & Gao, X. (2026). Effect of curcumin intervention on radiation-induced injury: A GRADE-based systematic review and meta-analysis. BMC Cancer, 26, Article 745. https://doi.org/10.1186/s12885-026-15985-5
Citation
CAM-Cancer Collaboration. Curcumin [online document]. http://cam-cancer.org/en/curcumin. October 2026
Document history
Updated in August 2026 by the CAM Cancer Collaboration. Updated in May 2020 by Ellen Conte, April 2014 by Klara Rombauts. Summary first published in May 2012 authored by Klara Rombauts and Liene Dhooghe.
Photo: mp23812986 from Mostphotos.com, licence via UiT The Arctic University of Norway.
