Taking iodine drugs in a large dose dose or for a long duration may cause anaphylactia or intoxication. When receiving a large dose of iodine complex, acute iodine poisoning may happen right away or a few hours later. There may appear symptoms of nausea, vomiting, abdominal pain or syncope. The major pathologic changes are characterized by angioneurotic edema, phartngeal edema and suffocation. Iodine drugs may also cause visual failure, weakness of accommodation, exophthalmos, retinal regeneration, retinal and macular edema, retinal vessel’s narrow, retrobulbar neuritis, toxic amblyopia, and optic atrophy. Following is a case report of acute renal failure and acute toxiclated optic neuritis caused by iodine poisoning due to mistaking of KIO_3. Taking iodine drugs in a large dose dose or for a long duration may cause anaphylactia or intoxication. When receiving a large dose of iodine complex, acute iodine poisoning may happen right away or a few hours later. There may appear symptoms of nausea, vomiting, Abdominal pain or syncope. The major pathologic changes are characterized by angioneurotic edema, phartngeal edema and suffocation. Iodine drugs may also cause visual failure, weakness of accommodation, exophthalmos, retinal regeneration, retinal and macular edema, retinal vessel’s narrow, retrobulbar neuritis, toxic amblyopia, and optic atrophy. Following is a case report of acute renal failure and acute toxiclated optic neuritis caused by iodine poisoning due to mistaking of KIO_3.