The patient, a manic depressive who was treated with lithium for three years, suddenly developed severe neurotoxicity and a glomerulonephritis-like syndrome. The author believes that the lithium toxicity was facilitated by hot weather with excessive sweating, gall bladder pathology with fever, and decreased water and salt intake. The patient improved except for a persistent hypertension. Propranolol not only improved the hypertension but alleviated a lithium-induced tremor as well.