Objective:In this study,we explored adverse reactions and patient background and performed a case/non-case study on a database of adverse reaction case reports in order aid the prevention of non-prescription drug abuse.Study Design:We conducted a case/non-case study on a database of adverse reaction case reports.Methods:We studied case reports of adverse reactions and addiction in Japan and extracted adverse reaction cases associated with taking antipyretic analgesics,antitussive drugs,antitussive expectorant drugs,hypnotic and sedative drugs,anti-anxiety drugs,and purgative drugs. We divided the extracted cases into an abuse case group (adverse reactions associated with non-prescription drug abuse,and divided its intended purpose or the purpose of abuse at the initial dose)and non-case group(other adverse reactions). We performed univariate logistic regression analysis on each item of investigation in the abuse case group and non-case group and calculated the odds ratio,p-value,and 95%confidence interval.Results:There were many abuse case reports of women 20-40 years old in the antipyretic analgesics abuse case group and many of them had liver/biliary lesions and chronic urological impairment. The most common reason reported for taking the initial dose of each drug was for its intended purpose.Discussion:It is important for pharmacists at community pharmacies and drugstores to be able to recognize the characteristics of patients who might be at risk of abuse and the adverse reactions and patient backgrounds elucidated in this study could be helpful in identifying them.