Sweating is a way for the body to regulate body temperature and dissipate heat, and there are differences between individuals. Some people sweat more and some sweat less, which is normal. However, some people usually sweat too much and their clothes are always oozing with salt stains, which should alert them to diabetes or hyperthyroidism. Diabetic patients often sweat more, especially the upper body sweat more. This is due to autonomic dysfunction caused by impaired glucose metabolism, resulting in increased sweat gland secretion. In addition, the increase in basal metabolic rate due to increased blood sugar is also one of the reasons why diabetic patients sweat more. The common symptoms of hyperthyroidism are fear of heat, excessive sweating and damp skin. This is due to the increased basal metabolic rate of hyperthyroidism, which increases peripheral blood flow and promotes heat dissipation. In addition to the above-mentioned causes, abnormal increase in sweating is also seen in women during menopause, rickets, pheochromocytoma, etc. Therefore, it is recommended to check blood glucose and thyroid function if there is usually an abnormal increase in sweating.