Iodinated glycerol is used as a mucolytic agent in the treatment of chronic obstructive pulmonary disease. Its efficacy is controversial, and reports of its toxicity are substantial. We report a case of chronic iodine poisoning in a patient with chronic obstructive pulmonary disease following 20 years of iodinated glycerol therapy. Reevaluation of the long-term use of this medication is encouraged. Monitoring long-term recipients of iodinated glycerol therapy for chronic iodine poisoning and drug-induced thyroid abnormalities is recommended.