Self-harm is a significant social and healthcare problem, with substantial morbidity and healthcare costs. It has strong links to further self-harm and to suicide. The current review is one of three that investigate interventions in preventing recurrence of self-harm, and it focuses on pharmacological treatment. The conclusions are limited by the small number and size of trials identified, and the low quality of evidence. No benefit on recurrence of self-harm was detected in three small trials of antidepressants, but the types studied are ones that are now less commonly used. A small trial of flupentixol suggested a possible benefit on repetition, but this has not been replicated. One small trial of lithium showed no benefit, but this was in contrast to a recent large meta-analysis showing a significant anti-suicidal effect of lithium when used to treat mood disorder. The review highlights important areas for further research.