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Indole-3-carbinol is a compound found in broccoli, cabbage, and Brussels sprouts. It can be taken by eating these vegetables or as a pill. Indole-3-carbinol has been used to lower signs of cancer in blood and urine.


200 to 400 milligrams once daily

What Research Shows

Not Enough Data to Assess

  • Cervical intraepithelial neoplasia A1
  • Vulvar intraepithelial neoplasia B1

Editorial process and description of evidence categories can be found at EBSCO NAT Editorial Process.

Safety Notes

It is likely safe to take indole-3-carbinol in small doses for a short time.C2 Nausea and imbalance may occur with high doses.C1 Not enough studies have been done to say whether it is safe to use for a long period. It is also not known whether it is safe to take by women who are pregnant or breastfeeding.


Talk to your doctor about any supplements or therapy you would like to use. Some can interfere with treatment or make conditions worse.



A. Cervical Intraepithelial Neoplasia

A1. Bell MC, Crowley-Nowick P, et al. Placebo-controlled trial of indole-3-carbinol in the treatment of CIN. Gynecol Oncol. 2000 Aug;78(2):123-129.

B. Vulvar Intraepithelial Neoplasia

B1. Naik R, Nixon S, et al. A randomized phase II trial of indole-3-carbinol in the treatment of vulvar intraepithelial neoplasia. Int J Gynecol Cancer. 2006 Mar-Apr;16(2):786-790.

C. Safety

C1. Indole-3-carbinol. Monograph. Altern Med Rev. 2005 Dec;10(4):337-342.

C2. Licznerska B, Baer-Dubowska W. Indole-3-Carbinol and Its Role in Chronic Diseases. Adv Exp Med Biol. 2016;928:131-154.

Last reviewed February 2020 by EBSCO NAT Review Board Eric Hurwitz, DC  Last Updated: 5/27/2020