Nineteen patients with metastases from histologically proved papillary carcinomas of the thyroid were treated by daily feeding of 0.2 to 0.3 gm (3 to 5 grains) of desiccated thyroid. Twelve of these patients (11 with metastases in lungs and 1 with an inoperable cancer and metastases in cervical nodes) have shown either regression of metastases or arrest of their growth for periods varying from 5 to 16 years and averaging 11 years. The cancers of seven remaining patients failed to respond to the treatment with desiccated thyroid or to any other type of therapy and the patients died with progressive growth of their metastases. The incidence of favorable response to feeding of desiccated thyroid was much higher in patients less than 40 years old than in those more than 40, and control was also obtained more frequently in those patients whose cancers had developed after radiation therapy of the neck for benign disease.