Rectal indomethacin has been proven to be effective for prevention of post-ERCP pancreatitis (PEP) but its impact on bleeding after biliary sphincterotomy (BABES) and cardiovascular mortality has not been extensively studied. We aimed to assess the effect of indomethacin on the rate of BABES and short-term cardiovascular mortality, particularly in patients receiving antiplatelet therapy (APT).In this double-blind, randomized, placebo-controlled, single-center study, 100 mg indomethacin or placebo was given within 1 hour before biliary endoscopic sphincterotomy to in-patients including those who are receiving APT (acetylsalicylic acid [ASA] and/or clopidogrel). Cardiovascular mortality and BABES were observed for 30 days.Of 576 randomized patients (289 indomethacin, 287 placebo), 87 patients used 100 mg/day ASA and 29 patients took 75 mg/day clopidogrel, among them 5 patients were on dual APT. The ASA and clopidogrel taking patients were older than patients without APT (P < 0.001), but these groups were similar in other parameters. BABES occurred similarly in different subgroups: indomethacin (8.0%) vs placebo (9.4%) (P = 0.56), ASA (10.3%) vs non-ASA (8.4%) (P = 0.54), clopidogrel (6.9%) vs nonclopidogrel (8.8%) (P > 0.99). No BABES was observed among patients on dual APT. There was no difference in cardiovascular mortality between subgroups (P > 0.99).Results indicate that single dose of 100 mg indomethacin does not increase BABES rate and cardiovascular mortality. This result is independent from administering antiplatelet agents.