This article indicates some of the social, emotional, organic factors involved in disturbing the balance of the geriatric psychological equilibrium and outlines the need for an appropriate rationale of treatment with modern tranquillisers and sedatives. Both the problem of individual variation to treatment and the need for delineation of contributory organic factors are emphasised. Some features of senile psychoses, delirium, and depression are considered. Reference is made to the principles of sedation and tranquillisation and a number of the more widely used agents are reviewed. Some of the more notable side e1fects are briefly outlined.Several clinical group studies involving the use of sedatives and tranquillisers were made on 143 patients from a generalhospital geriatric unit and 41 geriatric patients from a psychiatric hospital. The presence of mental illness in geriatric patients was not associated with long-term need for nocturnal sedatives but did tend to increase the duration of hospitalisation and reduce the chances of rehabilitation. It was found possible to manage all types of patients in the geriatric range without barbiturates, which are contraindicated. The need for a more flexible approach to medication in the psychiatric geriatric population is indicated. Some of the currently available ehemopsychotherapeutic agents, although useful, are of only limited value in aiding the more disturbed patients.