Written by Klara Rombauts, Italo M Cesari and the CAM-Cancer Consortium.
Updated March 9, 2017

Cat's claw (Uncaria spp)

Does it work?

Clinical trials

No controlled clinical trials investigating cat’s claw as an anticancer agent are available.

Two randomized clinical trials focusing on the reduction of side effects caused by chemotherapy are available 25,26. Both trials using an ethanolic extract of cat’s claw were published by the same group. The treatment consisted of oral tablets containing 300 mg of U. tomentosa dried ethanolic extract on top of chemotherapy. The control group received chemotherapy only. In the first trial (n=43), in this population and at the dose used, cat’s claw dry extract was not effective in reducing the most prevalent adverse events caused by treatment with 5-fluorouracil and oxaliplatin in colorectal cancer patients 25. In the second trial, cat’s claw was able to reduce neutropenia caused by a regimen consisting of fluorouracil, doxorubicin and cyclophosphamide and was also able to restore cellular DNA damage in the treatment of breast cancer. Cat’s claw showed no effect on antioxidant activity and on immune response. The dose of extract used in both trials was not tested in a dose-finding study but was based on the dose used in other (not cancer-related) clinical trials (discussed in the ‘Is it safe?’ section below (34-36)). Since these trials used an aqueous extract, different phytochemicals were extracted so there is no rationale to use this dose. It is unknown if the optimal dose was used in these trials.

One uncontrolled trial of 51 patients with advanced solid tumours assessed the effects of a 100mg dose of a dry extract of cat’s claw three times daily 39. Some improvements in overall quality of life, social functioning and fatigue were reported. None of the biochemical or inflammatory parameters assessed changed significantly and no tumour response was detected.

Case series/studies

Although a large number of case reports are available on the internet, none have been published in peer-reviewed journals.

Citation

Klara Rombauts, Italo M Cesari, CAM-Cancer Consortium. Cat's claw (Uncaria spp) [online document]. http://cam-cancer.org/The-Summaries/Herbal-products/Cat-s-claw-Uncaria-spp. March 9, 2017.

Document history

Revised in March 2017 by Barbara Wider.

Assessed as up to date in September 2014 by Barbara Wider.
Summary first published in February 2013, authored by Klara Rombauts and Italo M Cesari.

References

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