The assessments of deliberate self-poisoning patients carried out by 8 doctors and 8 nurses were compared. Both groups of staff had undergone special training in the assessment procedure. The adequacy of the assessments was determined by blind judges' ratings of transcripts of assessment interviews, comparisons of the types of treatment offered and repetition of self-poisoning The attitudes of the patients and their general practitioners were also investigated. No major differences were found between the assessments of the 2 groups of subjects. It is concluded that nurses under supervision of a senior psychiatrist can safely carry out the assessment of self-poisoning patients, provided they have received appropriate training. The findings suggest that services in which nurses assess most self-poisoning patients could be established in district general hospitals. This would reduce the demands currently placed on psychiatrists and physicians.