This study describes khat behavior, knowledge, and attitudes among Yemeni medical students (MS) and the effects of a seminar. The students completed a survey (n = 62); a subgroup participated in a discussion-based seminar and follow-up survey (n = 18). Although the students demonstrated knowledge about khat's health effects and considered it unacceptable for health professionals to chew khat, they disagreed that health professionals should advise patients to quit. Knowledge and attitudes improved post-seminar (not significant, except for a borderline significant increase in students correctly identifying khat as addictive; P = 0.063). Although effects were small, seminars may help health professionals address khat use in Yemen. Abstract published by arrangement with Taylor and Francis.