The results of treatment have been analysed in 173 patients with septicaemia during 1962–8. Between 1962 and 1965 various antibiotics were used, and shock was teated with vasopressor agents. Between 1966 and 1968 kanamycin was given initially, and shock was treated with corticosteroids and with intravenous fluid therapy monitored with a central venous pressure manometer. The mortality rate in 1966–8 fell to half that of the earlier period in patients with Gram-negative infections, and in those with shock. The reduced mortality in the latter was clearly associated with the use of a central venous manometer to control intravenous fluid therapy, though whether the reduction resulted from specific improvement in intravenous therapy or from the necessary closer observation of the patient is not clear. Staphylococcal septicaemia was common during both periods, and its mortality rate did not fall; hence methicillin together with kanamycin is now given initially in all cases.