Undoubtedly in the past, the prominence of the major seizures in epilepsy led to a focussing of attention on the fit itself, while the accompanying phenomena were ignored or received scant attention. More recently the study of the phenomena associated with the seizures has increased our knowledge, and we realise that by epilepsy we refer to a “symptom-complex” (1). With regard to metabolic processes which occur, and which appear to be of importance, very little has been elucidated, although much work has been done on examination of body fluids, etc. With the hope that it may induce others to join in an endeavour to throw some light on these processes, this is presented, as a preliminary contribution from work done here on the study of epileptic metabolism. The paper is devoted mainly to the consideration of the indoxyl voided in the urine. The clinical examination of the urine of epileptics has been carried on since December, 1905. In the paper attention is drawn to brief summaries which show some of the variations in the output of indoxyl, and a modification of Jaffe's test submitted, which, it is considered, makes for greater clinical accuracy.