Is DIM (Diindolylmethane) Safe To Take With Antibiotics?

In our latest question and answer, our pharmacist discusses whether or not there is an interaction between DIM (Diindolylmethane) and antibiotic drugs.


Hi, I was prescribed cefadroxil 500mg for my acne and was also planning on starting 3,3'-Diindolylmethane (DIM) supplements for hormonal acne. Are these safe to combine or are there any dangerous interactions between the two? Thanks for much for taking the time to answer!

Asked by Karisma On Jan 27, 2023

Answered by
Medical Content Reviewed By HelloPharmacist Staff

Published Jan 30, 2023
Last updated Apr 18, 2024

Key points

  • There is no known interaction between DIM (Diindolylmethane) and antibiotics, including cefadroxil.


Thanks so much for reaching out! Although there often is a lack of data regarding potential interactions between drugs and supplements, I could find no evidence that supports the existence of an interaction between DIM (Diindolylmethane) and antibiotics, including cefadroxil.

What Is DIM?

Diindolylmethane (DIM), also known by its chemical name 3,3'-Diindolylmethane, is a compound found in cruciferous vegetables such as broccoli, cabbage, and kale.

It is popularly used as a dietary supplement and often marketed as a natural way to support hormone balance, specifically estrogen imbalances, and as a 'detoxifying agent'.

Does DIM Interact With Any Drugs?

More research is definitely needed here, but there are some theoretical interactions between DIM and other drugs. We have a full list of potential interactions with DIM found on the interactions section of our website.

For one interaction example, DIM may reduce estrogen levels, and thus, could reduce the effectiveness of estrogen-type drugs.

Additionally, some small studies report that DIM could reduce the activity of a specific metabolizing enzyme, CYP1A2, and could potentially interact with any drug that is metabolized by it.

Some examples of drugs that are metabolized by CYP1A2 include:

  • Amitriptyline
  • Clomipramine
  • Imipramine
  • Duloxetine
  • Olanzapine
  • Tamoxifen
  • Fluvoxamine
  • Ramelteon
  • Tizanidine

While some antibiotics are known inhibitors of CYP1A2, like ciprofloxacin, the vast majority of antibiotics are not primarily metabolized by that enzyme, including cephalosporins such as cefadroxil and cephalexin.

Cefadroxil is actually very minimally metabolized at all. In fact, over 90% of the drug is excreted unchanged (i.e., un-metabolized) in the urine. There is just no evidence to suggest that DIM interferes/interacts with cefadroxil or most other antibiotics.

Final Words

Based on all the available information I could find, it appears there is no interaction between DIM and cefadroxil and they are likely safe to combine.

As always though, make sure your doctor knows all the medications you are taking, including supplements, so you can be appropriately monitored.

Thanks so much for using us! I hope you found this information helpful!


  • Ah receptor binding properties of indole carbinols and induction of hepatic estradiol hydroxylation, PubMed
  • 3,3'-Diindolylmethane induces CYP1A2 in cultured precision-cut human liver slices, PubMed
  • DURICEF Prescribing Information, AccessFDA

About the Pharmacist

Dr. Brian Staiger, PharmD

Dr. Brian has been practicing pharmacy for over 13 years and has wide-ranging experiences in many different areas of the profession. From retail, clinical, program development, and administrative responsibilities, he's your knowledgeable and go-to source for all your pharmacy and medication-related questions! Dr. Brian Staiger also has herbalist training and educational certificates in the field of medical ethnobotany. Feel free to send him an email at [email protected]! You can also connect with Dr. Brian Staiger on LinkedIn.

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