Abstract: An adverse drug reaction is defined as a response to a drug that is noxious and unintended and that occurs at doses normally used in man for prophylaxis, diagnosis, or therapy of disease or for the modification of physiologic function. Female patients are reported to have more adverse drug reactions, including hypersensitivity reactions, than male patients. The differences between male and female adverse drug reactions are based on the age group considered, the type of reactions, and the medication in question. Elderly patients are at the highest risk secondary to multiple and advanced disease states, polypharmacy, and pharmacokinetic differences in drug absorption, distribution, metabolism, and excretion. The risk of adverse drug reactions is decreased in patients who are properly screened for them. The diagnosis of an adverse drug reaction is difficult to establish; however, management is similar in most situations and involves discontinuation of the offending medication and monitoring the patent for resolution of symptoms. It is a health care provider's duty to report and document adverse drug reactions when they occur.