Combining colchicine and clarithromycin may result in life-threatening reactions. Reports of adverse reactions with coadministration of the antigout agent colchicine and the antibiotic clarithromycin are not new; however, the magnitude of harm was not previously recognized. In a recent study in the July Drug Safety, researchers examined case reports in the Food and Drug Administration's Adverse Event Reporting System (FAERS) database and the published literature. They identified 58 cases of serious reactions, including 30 fatal outcomes, in FAERS and an additional 20 cases, with four deaths, in the literature. Colchicine, used for the treatment of gout and familial Mediterranean fever, has a narrow therapeutic window. Clarithromycin greatly increases the bioavailability of colchicine and delays its clearance by the liver, potentially leading to toxic levels of colchicine when the drugs are used together. Coadministration of the drugs should be avoided.