This study aimed to evaluate the effectiveness of an educational intervention (Safe D.U.M.P) to improve the knowledge, attitude, and practice regarding the return and disposal of unused medications. Community-dwelling adults in Malaysia who could understand English were recruited from two healthcare events. Participants were asked to fill out the validated Return and Disposal of Unused Medications (ReDiUM) questionnaire (pre-intervention), view six educational intervention posters on how to dispose of unused medications (Safe D.U.M.P), then answer the ReDiUM questionnaire immediately after viewing the posters (post-intervention). A total of 390 out of 456 participants participated (response rate=85.5%). Most were female (71%) with a median age of 42 years. The overall knowledge of participants significantly increased from 60% to 80% (p<0.001). However, no improvement was seen regarding their overall attitude and practice. This outcome was as expected as it may be more difficult to improve attitude and practice (when compared to knowledge) with a single educational session.