THE LITERATURE contains many reports on the association of typhoid and pellagra. Bean and others, 1 in a review on secondary pellagra, assumed that in typhoid the rise in metabolism due to the prolonged fever leads to increased demands on the system of catalysts and brings about a state of deficiency. Sarma 2 in 1943 described the deficiency of nicotinic acid in patients with typhoid. Symptoms of this condition were glossitis and cerebral disturbances such as mania, confusion, delirium and melancholia. These symptoms could be relieved by treatment with nicotinic acid. Deficiency of nicotinic acid following typhoid has been observed in the Hadassah Rothschild University Hospital as well. 3 However, no laboratory investigations on the metabolism of nicotinic acid in typhoid have as yet been reported. The study reported here was undertaken with the purpose of examining the urinary excretion of nicotinic acid in typhoid and of establishing a possible relationship between the rate of excretion of