Involuntary medical detention is an increasing problem in many large teaching hospitals. Forty-two elderly patients involuntarily admitted for protective service to the general medical wards were compared with an age-matched group of 25 elderly persons voluntarily seeking care in the same institution. The comparison showed that most of the involuntarily admitted patients were more than 70 years of age, and more of them lived alone. On admission they had more dementia and dehydration but less urinary-tract infection than did the controls. Their hospital stays were longer. There was no difference between the groups with respect to discharge dispositions.