The aim of the study was to determine incidence, features and outcomes of the adverse drug reactions (ADR) among emergency department (ED) visits of S. Giovanni Battista Hospital in Turin. We evaluated 16.055 patients among ED visits in a period of five months; the mean age was 59.6 +/- 20.2 year (range 17-93 y; 8.054 women and 8.001 men); 426 (2.6%) had ADRs, and 91 (21.4%) were admitted to the hospital. In multivariate analysis only the number of medicines was positive correlated with ADR. The drugs most frequently ADR-related were: anticoagulants (21.8%), antibiotics (17.6%), NSAIDs (9.9%), hypoglycaemic agents (9.6%), ACE-inhibitors (4.7%), antipyretics (4%) and alfa-litics (3.3%); the most common clinic events were: gastrointestinal bleeding (21.1%), rash (19.7%), confusion (23.9%), hypoglycaemia (8.4%), dyspnoea (7.0%), syncope and wheezing (5.6%), gastrointestinal bleeding (2.8%), anaemia (2.8%), haematomas (4.2%), vomiting (4.2%). Factor associated with increased ADR-hospital admission were increasing age (over 65 years old), gastrointestinal diseases, dementia and ADL-dependence. ADR-patients' Emergency Department mortality was higher than noADR-patients' one. The mean duration of hospitalization was higher in ADR-patients. It is necessary to reduce the number of drugs and improve studies and prevention strategies targeted to reduce the impact of ADR, specially in the elderly population.