The two faces of medicine. The incidence of adverse events, adverse drug reactions and medication errors in hospitals. The incidence of adverse drug-induced events/reactions and medication errors in primary care. The stages at which drug reactions and medication errors occur in hospitals. Types and causes of adverse events and medication errors in hospitals. Risk factors predisposing to adverse events and medication errors. The cost of medical errors. Summary of the problem of injury induced by drugs and medication errors. Errors in healthcare: a major cause for concern. Changes in the UK litigation process as a potent tool to influence errors and complaints. Reducing medical errors. Implications of error reduction for undergraduate teaching. Have the undergraduate course failed to deliver students knowledgeable in pharmacology and therapeutics? Litigation and negligence. Implications for professional and continuing professional aspirations in healthcare. Future directions for professional expertise in healthcare: a conundrum. Conclusions. Appendices.