Naganuma M, et al. - The safety and efficacy of Indigo naturalis (IN) were examined in patients with ulcerative colitis (UC). The researchers found 8 weeks of IN (0.5–2.0 g per day) to be effective in inducing a clinical response among patients with UC in a randomized, placebo-controlled trial. IN, however, was not recommended yet due to the potential for adverse effects, including pulmonary arterial hypertension.