A 59-year-old woman had been admitted to our hospital every two months for over a past year because of severe right abdominal pain. Colonoscopy revealed dark blue mucosa extending from the cecum to the transverse colon, and abdominal computed tomography showed wall thickening and linear calcification along the wall from the cecum to the transverse colon. Based on these findings, the patient was given a diagnosis of idiopathic mesenteric phlebosclerosis. Subsequently, we found that she had been a long-term user of a Chinese herbal product containing Gardeniae fructus for allergic rhinitis. After discontinuing the product, the patient has been free of abdominal pain for a year.