Effects of Burdock tea on recurrence of colonic diverticulitis and diverticular bleeding: An open-labelled randomized clinical trial.

Colonic diverticular bleeding (CDB) and acute colonic diverticulitis (ACD) show high recurrence rates. The establishment of optimal strategies that prevent the recurrence of CDB and ACD is a major concern among gastroenterologists. This study aimed to assess the efficacy of burdock tea for preventing CDB and ACD recurrences. Newly diagnosed patients with CDB (n = 91) or ACD (n = 70) were randomly assigned into two groups. The experimental group received 1.5 g of burdock tea three times a day, whereas the control group did not receive any treatment. The median (interquartile range) of observation for recurrence of CDB or ACD was 22.0 (14.1) months and 30.3 (18.6), respectively. The burdock tea treatment showed significant preventive effects on recurrence of ACD. A lower ACD recurrence rate (5/47 [10.6%] vs. 14/44 [31.8%]) and longer recurrence-free duration was observed in the burdock tea group (59.3 months [95% CI: 54.0-64.7] vs. 45.1 months [95% CI: 37.1-53.0] by the Kaplan-Meier analysis; p = 0.012 by log rank test) than in the control group, although there was no significant preventive effects on the CDB recurrence. This randomized clinical trial demonstrated that daily intake of burdock tea could be an effective strategy for prevention of ACD recurrence, but not for CDB recurrence.