This study aimed to determine whether the style of service provision and the substance ingested in overdose influenced the hospital management and direct costs of self-poisoning at six UK hospitals. Of 1778 self-poisoning episodes presenting over a 5-month period, fewer than half resulted in a specialist assessment. Episodes were more likely to lead to admission or psychosocial assessment if the hospital had a self-harm team, or if the act involved subtances of high lethality. The mean costs of overdose were greater in hospitals with a self-harm team (£378 (SD: 1242) v. £289 (SD:751), and greater for drugs of higher lethality such as tricyclics (£634 (SD:911) and poly drug overdoses (£449 (SD:1955)), than for all drug classes (£333 (SD:1027). This study confirms the generally poor level of UK self-harm service provision and suggests the style of services and the drugs ingested both have a significant impact on the hospital management and costs of self-poisoning.