1. Medication histories are important in preventing prescription errors and consequent risks to patients. Apart from preventing prescription errors, accurate medication histories are also useful in detecting drug-related pathology or changes in clinical signs that may be the result of drug therapy. A good medication history should encompass all currently and recently prescribed drugs, previous adverse drug reactions including hypersensitivity reactions, any over-the counter medications, including herbal or alternative medicines, and adherence to therapy. 2. Medication history errors, such as omitting drugs erroneously, are common and often have the potential to harm the patient. Hypersensitivity reactions are often poorly documented or not explored in detail, which may lead to unnecessary avoidance of a drug. Accurate documentation of concomitant herbal or alternative therapies is rare, despite the importance they may have in causing adverse effects or drug-drug interactions. Polypharmacy, specific drugs, and clinical specialty can affect the risk of medication history errors. 3. There are various strategies to reduce medication history errors. Pharmacists are better at taking an accurate medication history than many physicians or nurses. In the context of acute hospital admissions they reduce error, the risks of adverse drug reactions, and prescription costs. Electronic prescribing may reduce transcription errors, but it can facilitate other errors and still depends on an accurate medication history. 4. Education of prescribers, both in clinical pharmacology and in taking accurate medication histories is vitally important in reducing errors.