OBJECTIVES: To assess the prescription drug knowledge and the impact of counseling on it in patients visiting a public teaching hospital. METHODS: A standardized questionnaire of prescription drug knowledge that embraces 8 questions e.g. drug name, indication, side effect, dose, frequency of dosing, dosage schedule, storage and missed dose action of prescription drugs was used. Education level was set as group-1 illiterate patients, group-2 education up to secondary school and group-3 graduate patients. The patients were scored 1 for every correct answer, with a maximum of 8. The overall scores were then categorized as low (<3), medium (3–6) and high (>6). Patients were counseled by oral, written, oral-pictorial combine, written-pictorial combine and oral-written-pictorial combine for all the questions. Post counseling evaluation was performed to assess the impact of patient counseling. RESULTS: Total 753 patients were assessed. Patient’s knowledge about prescription drug name, side effect, dose and missed dose action was poor. The prescription drug knowledge score was low (<3) in group-1 and the patients of acute drug treatment. Whereas, medium (3-6) knowledge score was observed in group-2, group-3 and patients of chronic drug treatment. The overall score was improved from 3.43±1.47 to 6.20±1.26 after counseling in all enrolled patients. After counseling overall score was improved from 2.88±1.40 to 6.01 ± 1.16 and from 3.71±1.43 to 6.30±1.29 in patients of acute and chronic drug treatment, successively. Improvement in overall score was observed from 2.78±1.37 to 5.55 ± 1.19, from 3.52±1.10 to 6.32 ± 0.88 and from 4.49±1.55 to 7.25±1.17 in educational group-1, group-2 and group-3 after counseling, respectively. CONCLUSIONS: Patients having low level of education, acute drug treatment and especially female patients know little about their prescribed drugs. Patient counseling about their prescribed drugs will help to improve the patient’s compliance and may lead to achieve better patient outcome.