Amiodarone, 2-N-butyl-3-(4'diethylaminoethoxy-3',5-diiodobenzoyl)benzofuran, also known as Cordarone, is presently under clinical investigation in the United States. It is an alpha and beta antagonist and is extremely effective in treating otherwise uncontrollable ventricular arrhythmias. To date, 27 patients participating in our ongoing study since 1977 have had corneal deposits. The deposits are in the corneal epithelium basal cell layer, and occur in stages (mild, moderate, and severe), which seem to correlate with dosage and duration of treatment. Vision is rarely diminished by these deposits, and if it is, discontinuation of the drug therapy will cause regression of the deposits with eventual return to normal beginning within two to four weeks but possibly taking as long as 1 1/2 years. The deposits look similar to those seen in chloroquine toxicity and Fabry's glycolipidosis. Other adverse effects reported in the European literature include thyroidopathy, cutaneous pigmentation, and neuromyopathy.