In recent years, one of Japan’s policies for controlling increased medical expenses is promoting self-medication. Owing to their influence on the health of young people, energy drinks (a caffeine-containing beverage) have attracted attention. However, only a few surveys have evaluated their use in Japan. Therefore, we conducted a questionnaire survey on university students on self-medication interest and energy drink use trend, involving 180 students aged 18-26 years. The results showed 28.3% of the students were interested in self-medication and 4.4% were knowledgeable on the self-medication tax system. Additionally, 73.9% of them used over-the-counter (OTC) drugs, especially common cold medicines (65.0%). Further, 77.2% of them consumed energy drinks, mainly to stay awake (61.9%), and most frequently from evening to midnight (54.7%). Furthermore, 26.6% of the students had experienced discomfort or poor health when taking energy drinks, with the most common symptoms being “tachycardia” (n＝13) and “sleep disorders” (n＝12). Pharmacy and drugstore pharmacists could contribute to caffeine overdose prevention by educating the public on the caffeine content of common cold medications and various foods and drinks such as energy drinks. It is desirable for future studies to investigate in depth the usage of caffeine-containing beverages, including energy drinks.