Evidence of interactionPending review

The short answer

Yes, there is evidence of an interaction with tamoxifen. In a 2019 study, 16 people with breast cancer took tamoxifen alone, with curcumin capsules, and with curcumin plus piperine, a single compound taken from black pepper. Endoxifen, the active substance the body makes from tamoxifen, fell by 12% with curcumin plus piperine. The 8% fall with curcumin alone could have been chance.

Memorial Sloan Kettering cites reports on turmeric with paclitaxel, but we have not yet checked the original papers, so we do not describe them here. Other cancer drugs have lab data only. These studies used capsules, not haldi in food, which is a different exposure and has not been tested. If you are on tamoxifen or chemotherapy, tell your oncologist before you take turmeric or curcumin supplements.

Paclitaxel is given in India as Paclitax, doxorubicin as Adriamycin and cyclophosphamide as Endoxan, among other brands.

At a glance

What was seen	How it may work	Direction	Evidence
Lower endoxifen (active tamoxifen) levels with curcumin plus piperine[1]	Not established	Less active tamoxifen in the blood	Small clinical study
Curcumin altered the effect of doxorubicin, camptothecin and mechlorethamine on cancer cells[2]	Laboratory experiments	Clinical relevance not known	In vitro

No listing is not a clearance. A missing interaction here never means a combination is safe.

The evidence, study by study

Crossover study in breast cancer, 2019 Small clinical study

Sixteen people with breast cancer on daily tamoxifen went through three 28-day periods: tamoxifen alone, with curcumin (1,200 mg three times a day), and with the same curcumin plus 10 mg of piperine three times a day. Endoxifen exposure fell 7.7% with curcumin, which was not statistically significant, and 12.4% with curcumin plus piperine, which was. The study measured drug levels, not whether the cancer came back.[1]

Laboratory studies, as reported by Memorial Sloan Kettering In vitro

MSK lists lab studies in which curcumin altered the effect of doxorubicin, camptothecin and mechlorethamine on cancer cells, and says their clinical relevance is not known. Lab findings like this show a possible route for an interaction. They do not show that one happens in people.[2]

What your doctor may watch for

The side effects and blood tests your cancer team already follows. Tell them about every supplement, because the effect differs from one cancer drug to another.[2]

What to tell your prescribing doctor

You can read this out, or show them this page:

“I am taking, or planning to take, turmeric or curcumin (name of product, how much, and whether it contains piperine or black pepper extract) during my cancer treatment. A study found curcumin with piperine lowered the active form of tamoxifen. Is it a concern with my treatment?”

Withheld until review

Dose adjustments and any “no known interaction” clearance appear only after a vaidya on our medical board has reviewed this page. Why we hold these back

Questions people ask

Is haldi in food a problem with tamoxifen?

We found no study that tested cooking amounts of haldi with tamoxifen. The trial used high-dose curcumin capsules, which are a different exposure. That does not mean food amounts have been tested, so mention them if you eat a lot of haldi or take haldi doodh daily.[1]

Does it matter if my curcumin contains piperine?

It seemed to. In the 2019 study, the fall in endoxifen was larger and statistically clear only when piperine was added. Check the label of your product for piperine or black pepper extract.[1]

Interaction

Sources

Updated 4 November 2026

Taking turmeric with other medicines? A vaidya can check your full list.

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Turmeric with tamoxifen and chemotherapy