Medical mistakes are common in drug prescription. Cases of irrational, inappropriate or ineffective prescribing can render a doctor legally accountable for deviating from the standard of care. Based on Portuguese, French and Italian case law, this paper addresses some of the most recurrent types of liability involving drug prescription: lack of information on drugs, errors in drug dosage, selection of a wrong drug, drug interactions, failure to follow up, off-label prescriptions and at-a-distance prescriptions. Following this, the paper concludes with some recommendations for preventing liability under these scenarios.