The effects of quinine and paracetamol on fever were studied in 21 adult patients with acute uncomplicated falciparum malaria. Quinine alone (n = 7) had no significant effect on fever, whereas paracetamol given 2 h after quinine (n = 7) or 2 h before quinine (n = 7) reduced temperature by a mean of 2.1 degrees C (standard deviation [SD] 0.95) and 2.1 degrees C (SD 0.79) respectively. A temperature reduction of 1 degree C was associated with a mean decrement of 9.7 beats/min (SD 3.3) in the pulse rate. Quinine does not possess useful antipyretic activity.