After high-dose 131 iodine nail or focal clearance treatment for differentiated thyroid cancer, there will be certain radiation effects on salivary glands, gonads and other organs. Therefore, it is important for every patient to know how to prevent and reduce these side effects as much as possible. The main measures include: 1. After taking 131I, it is advisable to drink more water, empty the urine often, and defecate at least once a day to reduce the radiation gathering in the bladder and intestines to the gonads and other organs. 2, available acidic drinks or food to promote saliva secretion, to reduce the damage of radiation to the salivary glands. 3, oral corticosteroids, such as prednisone, etc.