BACKGROUND: Paracetamol (acetaminophen) is the most common self-poisoning agent in the UK and a leading cause of fatal hepatotoxicity. Following legislation in 1998 to limit pack sizes, beneficial effects on paracetamol-related mortality and morbidity were reported in England. However, there are still over 100 deaths a year and evidence of breaches of sales guidelines. AIM: To investigate characteristics of people taking larger paracetamol overdoses and compliance with sales guidelines, to inform possible further initiatives to reduce paracetamol fatalities. DESIGN AND METHODS: Interview study of 60 general hospital patients who took overdoses of over 16 paracetamol tablets (8 g). RESULTS: Half of all paracetamol overdoses involved over 16 tablets. Patients were predominantly young (three-quarters aged 16-40 years) and female (58.3%); over half (53.3%) had taken a previous paracetamol overdose. Three-quarters said they wanted to die. Half took the overdose within an hour of first thinking of it, half (53.3%) took tablets already in the home and 58.3% bought tablets specifically for the overdose. Ten people tried to buy more than 32 tablets in one transaction; four succeeded. Most knew that a paracetamol overdose could cause death or permanent damage (88.3%) and harm the liver (80.0%) but 70.0% thought they would lose consciousness. Warnings on packs had little deterrent effect. Media and internet influences were identified. Patients chose paracetamol because it was cheap and easily available. CONCLUSIONS: Further measures to reduce breaches of sales guidelines and the dangers of paracetamol overdose are required. Media and internet site producers should follow guidelines on reporting suicide.