Development of pulmonary arterial hypertension following long-term Qing-Dai use for ulcerative colitis

Indigo Naturalis in Inflammatory Bowel Disease: mechanisms of action and insights from clinical trials

“…In the same study, one case was reported where liver levels increased 10 times the upper limit of normal. Recently, many cases of pulmonary hypertension have been reported in patients taking green tea for UC [ 58 - 60 ]. These cases have a common rapid improvement after stopping taking IN.…”

Letter by Frumkin Regarding Article, "Dramatically Improved Severe Pulmonary Arterial Hypertension Caused by Qing-Dai (Chinese Herbal Drug) for Ulcerative Colitis."

“…There are 4 additional published cases of PAH believed to be associated with the use of indigo naturalis (also known as Qing-Dai). [3][4][5][6] Indigo naturalis is an herbal medicine derived from fermented leaves and stems of plants and is a component of crude drugs used in traditional Chinese medicine. While indirubin is an active ingredient of indigo naturalis (Qing-Dai), there are numerous ingredients in indigo naturalis (Qing-Dai) that are aryl hydrocarbon receptor (AhR) agonists, and AhR agonism has been associated with the development of pulmonary hypertension in several animal models.…”