The study of the effects of tolbutamide and dietary carbohydrate in multiple sclerosis was prompted by an almost complete remission of symptoms in a patient soon after initiation of tolbutamide therapy for acne. Tolbutamide was alternated with placebo capsules in six of the seven patients studied, the dosage ranging from 0.5 to 1.5 Gm. per day. The amount of dietary carbohydrate was frequently changed between high and low values. In all cases, except when a high-corbohydrate diet was started, remission was evident after administration of tolbutamide, whereas placebo capsule substitution was followed by exacerbation. In the majority of patients, a low-carbohydrate diet was beneficial, a high carbohydrate diet detrimental.