In this article, we quantify a clinical observation that non-Ashkenazi Jews having a half-mustache on the lower part of their upper lip have a high frequency of peptic ulcer and dyspepsia. The prevalence rate for peptic ulcer and dyspepsia was 33.6% and 44.9%, respectively, in the study group, compared with 11.2% and 24.3% in the control group. Although psychological examination was not conducted, we hypothesize that subjects who trim their mustache in this manner have obsessive and perfectionist characteristics and show features of extroverted personality. We speculate that these traits may be contributory to the development of peptic ulcer and dyspepsia.