Pharmaceutical management involves drugs left unused at the patients’ homes (commonly called “zanyaku”). The definition of the term zanyaku, however, is not generally agreed upon. In this study, a survey was conducted on diabetic patients in an attempt to find out what they considered “zanyaku” to mean. We surveyed diabetic patients who visited healthcare institutions or pharmacies during the month of September 2013. Aggregate analysis was performed on the 209 responses collected. To the question “What is your impression when you hear the word zanyaku?” 55 respondents (32.4%, the highest rate) out of a total of 170 replied, “Necessary doses that I will use,” followed by “Leftover doses exceeding a certain amount.” (30.0%, 51 respondents). The results showed that individual patients had different ideas of what zanyaku meant. When managing zanyaku, pharmacists may need to collect information based on the patients’ ability to self-manage drugs.