Background: The history of adverse reactions to drugs goes back more than 2,000 years. In the 10th century AD in Italy had the power to hang druggists who sold poisonous or harmful drugs. The present study was done to estimate the incidence of ADRs in patients, to determine the pattern of the risk factor associated with ADRs and to find the outcome of reported ADRs. Methodology: A prospective study was conducted among patients who developed an ADR during 12 months in the GSVM Medical College, Kanpur, Uttar Pradesh. Results: Out of total 185 ADRs 54 (29%) were of type A, 94 (51%) were of type B, 27 (15%) were of type C and 10 (5%) were of type D. Over all 25 (13%) ADRs were found in < 12 years age group, 107 (58%) in 12 – 45 years age group and 53 (29%) were in > 45 years age group. Out of 185 ADRs 105 (57%) were in male patients and 80 (43%) were in female patients. Out of total 185 ADRs 44 (24%) were found in summer, 50 (27%) in rainy, 34 (18%) in autumn, 29 (16%) in winter and 28 (15%) in spring. Conclusions: Among type A ADRs, 41% were mild, 57% moderate and 2% severe. Among type B ADRs, 23% were mild and 77% moderate. Among type C ADRs, 78% were mild and 22% moderate. Among type D ADRs, all (100%) were of moderate severity.