Recently, caffeine consumption in Japan is thought to have increased. Although caffeine had been considered to be harmless, there have been studies which suggests an association between caffeine and health and give rise to vigorous discussion. However, in Japan, there have been few epidemiological studies on caffeine consumption among a general population. A questionnaire survey was conducted among medical students and the results were as follows: 1) High dose users (estimated daily caffeine use is 250 mg or more) were observed in 15.2% and the proportion was higher in males than in females. 2) The respondents gave sleepiness, dry mouth and so on, as reasons for taking caffeine beverages, and gave, as the effects of caffeine, becoming clear-headed, shaking off sleepiness, and epigastric discomfort or pain. 3) A third of respondents have experienced taking caffeine tablets and ampules to shake off sleepiness and, in males, the more caffeine they had daily, the more who reported the experience. 4) Caffeine consumption has an association with alcohol use and smoking habit among males.