Introduction Unused and expired medicines are potentially toxic substances that should be managed effectively to avoid possible environmental hazards. The absence of well-defined protocols in India regarding the proper disposal of unused, unwanted, and expired medications raises concerns about the potential for accidental poisoning and environmental threats. Consequently, this research was conducted to evaluate the disposal practices of medications within both urban slum households and pharmacies. Methods This questionnaire-based, mixed-method study was conducted among 385 general public residing in urban slums and 10 registered pharmacies in Bhubaneswar city, India, from September 2020 to August 2021. A semi-structured questionnaire was framed to collect data from the households and the pharmacies; key informant interview was carried out among expert members regarding the disposal of expired medicines. Results Results found that 82.1% (316/385) of the study population threw unused drugs in dustbins, whereas only 2.6% (10/385) returned the medicines to the pharmacy. The most common reason for leftover medicine was the stoppage of drugs on symptomatic relief (53.2%, 205/385), followed by changes in prescription by doctors (18%, 69/385). Out of 10 pharmacies, seven pharmacies disposed of expired drugs in general dustbins. Conclusion Our findings indicate that a majority of the participants tend to dispose of medicines in an unsafe manner. Conversely, the responsible disposal of medications is significantly influenced by patient education. Hence, healthcare professionals are better positioned to impart knowledge to the public, fostering awareness about the proper storage and safe disposal of unused, unwanted, and expired medicines.