Weight, skinfold thickness, grip strength and the total-body-potassium content were measured in 13 healthy elderly subjects before and after a three-month course of potassium supplements given in a dose of 36 mmol per day. There were no significant changes in the total-body-potassium content or in the ratio of total body potassium to lean-body mass. An increase in the right-hand grip strength may well have been a placebo effect.