Diffuse thyroid lesions can be seen in a variety of diseases, such as nodular goiter, Hashimoto’s thyroiditis, Graves’ disease, thyroid cancer, etc. Diffuse thyroid lesions alone cannot be assessed to be dangerous or not, and need to be combined with other tests to determine that in most cases it is not considered to be dangerous, but if it is caused by thyroid cancer, then it is more dangerous. Diffuse thyroid lesions are a pathological state of the thyroid gland, which can be seen in a variety of diseases, such as Hashimoto’s thyroiditis, Graves’ disease, nodular goiter, subacute thyroiditis, etc. Most of these diseases are not dangerous. However, Graves’ disease with hyperthyroidism inducing a thyroid crisis or Hashimoto’s thyroiditis with hypothyroidism inducing a coma with mucous edema are more dangerous. In addition, diffuse thyroid lesions can be seen in thyroid cancer, which is more dangerous and requires surgical treatment. When diffuse thyroid lesions occur, it is necessary to go to the hospital and undergo relevant examinations to make a definitive diagnosis and treatment.