Abstract There are few psychiatric studies of serious self-injury patients admitted to general hospitals. In order to better characterize patients whose overdoses are serious enough to require hospitalization on a toxicology service, we describe 207 consecutively admitted, serious overdose patients (OD), all of whom were psychiatrically evaluated. They were compared with 53 nonoverdose self-injury cases (NO) and 79 medical/surgical patients with suicidal ideation (SI) who were routinely referred for consultation during the same 2-year period. All data were contemporaneously compiled into a computerized database and analyzed. The attempters (OD and NO) were younger than the ideation patients (SI). The OD group was predominantly female (60%) and the NO and SI groups were predominantly male (72%). More OD cases were separated and more SI cases were widowed. Similar to previous reports, prior psychiatric contact was high in all groups. DSM-III-R diagnoses of depression, adjustment disorders, and substance abuse were most common in each group, without group differences. Only borderline personality disorder distinguished the groups, and the OD group had significantly more borderline patients. There were no seasonal differences for admission dates between groups. SI cases had longer hospital lengths of stay and were least likely to require further psychiatric care after discharge from the general hospital. Attempter groups were more similar to each other than the ideation patients. Clinicians should maintain a high index of suspicion for Axis I disorders in suicidal general hospital patients, though female borderline patients are particularly associated with the serious overdose method.