Published experiences with severe toxicity with intravenous colchicine have been reviewed. All reported cases reflect inappropriate use of the drug. Therapeutic rules for colchicine have been derived from this information: (1) Single intravenous doses should not exceed 2-3 mg, and cumulative total doses for an attack should not be more than 4-5 mg. (2) Patients should receive no more colchicine by any route for 7 days. (3) Colchicine doses must be reduced in the presence of renal or hepatic disease, and in the older patient with apparently normal renal function. (4) Intravenous colchicine doses should be half the size of oral ones. (5) Absolute contraindications to intravenous colchicine therapy for acute gout include combined renal and hepatic disease, creatinine clearances below 10 cc/min, and extrahepatic biliary obstruction.