Colchicine is a commonly used drug for the treatment of gout and other indications. Toxicity from intentional oral overdoses of colchicine has been reported. Two cases are reported here in which colchicine was given by intravenous injection, and patients presented with multiorgan toxicity. The authors tested plasma and urine colchicine levels in these patients and found them significantly elevated. Testing of the vial from which the colchicine injections were given showed that the vial was mislabeled and contained 10-fold greater concentration of drug than the labeling indicated. These patients thus received a bolus dose of 20 mg of intravenous colchicine rather than the intended 2-mg dose. An intravenous dose of this magnitude has not previously been reported.