We evaluated the prevalence of valvular regurgitation in patients who have taken anorectic medications. Two-dimensional echocardiograms with color flow Doppler were recorded in 200 consecutive patients referred to a major metropolitan hospital for evaluation of cardiac function because of a history of anorectic medication use. Each patient filled out a questionnaire at the time of the visit or through telephone contact. Each echocardiogram was reviewed by 2 observers. The degree of valvular regurgitation was graded by a consensus of both observers. Significant valvular regurgitation was defined as at least moderate mitral regurgitation (MR) or at least mild aortic regurgitation (AR), as recommended by the Food and Drug Administration and Centers for Disease Control and Prevention. For all patients having taken anorectic drugs, there was a 5% prevalence of at least moderate MR, a 12% prevalence of at least mild AR, and a 16% prevalence of significant MR and/or AR. Patients with significant AR and/or MR were older than those without significant valvular regurgitation (49+/-12 vs 44+/-11 years, p = 0.03). Patients with significant MR and/or AR had a longer exposure duration (8 vs 6 months, p = 0.049) to anorectic drugs. There was no difference in weight loss between those with and without significant regurgitation (p = NS). The 2 largest subgroups were patients who took the fenfluramine-phentermine combination (n = 127) and those who took dexfenfluramine alone (n = 42). The prevalence of significant MR and AR was 5% and 9% for the fenfluramine-phentermine group and 0% and 14% for the dexfenfluramine group, respectively. There was also a high subthreshold level of MR and AR in these patients.