A double-blind, placebo-controlled, cross-over trial of quinine in leg cramps occurring at rest was conducted in 22 elderly cramp sufferers. Despite demonstration of impaired quinine elimination in the elderly, prescription of the traditional dose of 300 mg quinine bisulphate at night failed to produce a significant (P = 0.1) reduction in the number or severity of cramps. There was a significant relationship between serum quinine concentration and attenuation of cramps. However, the simple expedient of increasing the nightly dose of quinine may carry the concomitant risk of cinchonism.