Indigo Naturalis Very Effective for UC, but Safety Concerns Exist

Indigo naturalis (IN; also called Qing-Dai) is a Chinese herbal medicine made from the same plant used to make blue dyes. There is some evidence that IN induces interleukin-22 and promotes mucosal regeneration in ulcerative colitis (UC).

In the current study, 86 patients with moderate to severe UC with disease extending to at least the sigmoid were randomized to receive one of three different doses (0.5, 1.0, or 2.0 grams) of IN or placebo for 8 weeks. Patients were evaluated at weeks 0, 2, 4, and 8.

Compared with placebo, at week 8, rates of clinical response (primary endpoint) were 5 to 6 times higher with all doses of IN, clinical remission rates were 8 to 12 times higher with the two higher doses of IN, and mucosal healing rates were 3 to…