OBJECTIVES: Toxicovigilance studies were carried out with the aim to determine the health hazards, treatment and outcome of therapeutic drug overdose. METHODS: All therapeutic drug poisoned patients admitted to a tertiary care South Indian hospital. were evaluated for predisposing factors manner of exposure, severity at admission, treatment, hospitalization period, clinical status at discharge, , in order to implement medication safety programs. RESULTS A total of 200 patients were admitted with therapeutic drug overdose. A total of 153 cases intentionally ingested the drugs, while 29 cases had overdose during routine therapy, and 18 cases had ingested the drugs accidentally. Depression was the major predisposing factor for intentional self harm. Most of the poisoning with therapeutic drugs occurred due to intentional self harm n=153 (76.5%). Other manner of exposures include overdose during therapeutic use n=29 (14.5%) or accidental exposure n=18 (9%). There was a significant (P<0.001) association of employment and occupational status on the manner of exposure. The mean GCS, APACHE II scores, PMR and PSS for all the patients was 8.46± 3.6; 20.63 ± 5.0; 38.58 ± 16.1 and 2.96 ± 0.79 (Mean±SD) respectively. The mean GCS score was significantly (P=0.033) different between various class of poisoning. The APACHE II scores were not significantly (P>0.05) different between various drug classes. The mean severity scores was significantly (P=0.016) different between various class of drugs. The treatment provided was empirical and symptomatic with differing decontamination procedures. The average hospitalization period was 6.68 ± 4.9 days with a median of 6 days range (3-8). Majority of them 189(94.5%) improved, while 5 patients were discharged with severe sequele, and six patients expired during hospital stay. CONCLUSIONS: The extent of harm caused due to therapeutic drug poisoning can be minimized by systematically estimating the severity at triage and providing treatment as per standardized guidelines.