This study indicated a direct, statistically significant association between tranquilization of hospitalized psychiatric patients aged 55 and older and the development of physical illness or injury. This was not demonstrated for patients of 54 and younger. Dosage or drug derivative could not be related to the development of illness nor could physical diagnosis be related to tranquilization. The data did suggest that tranquilization may be less compatible with the chronic brain syndrome than with other psychiatric conditons. We conclude that tranquilization of the psychiatric patient over 55 is associated with the subsequent development of nonfatal disease or injury of sufficient severity to warrant infirmary admission.Abstract Teaser