Indole-3-Carbinol (I3C) is a compound found in cruciferous vegetables such as broccoli, cabbage, and Brussels sprouts. Its use in supporting or treating abnormal Pap smear results, particularly those associated with cervical dysplasia and human papillomavirus (HPV) infection, is backed by some scientific evidence, though it is not yet considered standard therapy.

Several clinical studies have investigated I3C’s potential effects on cervical intraepithelial neoplasia (CIN), a precursor to cervical cancer often detected via abnormal Pap smears. A notable double-blind, placebo-controlled trial (Wong et al., 1997, Gynecologic Oncology) found that oral I3C supplementation (200 mg and 400 mg daily) led to complete regression of CIN in 4 of 8 women at 200 mg and 4 of 9 women at 400 mg, compared to none in the placebo group. Other smaller studies and in vitro research suggest that I3C and its metabolites may modulate estrogen metabolism, promote apoptosis in abnormal cells, and inhibit the activity of HPV oncogenes.

While these findings are promising, the overall quality of the evidence is moderate, with small sample sizes and lack of large-scale, long-term studies. As such, I3C is sometimes used as a complementary approach for women with abnormal Pap smears or CIN, but it should not replace established medical treatments. Its use should always be discussed with a healthcare professional.