Loss of appetite, emaciation and drowsiness in the elderly can be considered to be related to hypothyroidism, Parkinson’s syndrome or neoplastic diseases (e.g. stomach cancer, liver cancer, etc.). 1. Hypothyroidism: Hypothyroid patients have lethargy and loss of appetite due to hypothyroidism or thyroid hormone resistance, reduced metabolic rate as well as decreased sympathetic excitability, which can cause malnutrition and other problems in the long term. 2. Parkinson’s Syndrome: patients may have static tremor, autonomic disorder, motor retardation, etc. Other non-motor symptoms such as fatigue, depression, etc. may affect the physical functions. 3. Tumor disease: For example, elderly patients with stomach cancer and liver cancer will have symptoms such as emaciation, loss of appetite, mental weakness and fatigue due to the consumptive nature of the tumor. Long-term emaciation, loss of appetite and drowsiness of the elderly may also be caused by other reasons, so they need to consult doctor in time, improve relevant examination to find out the cause of the disease, and follow the doctor’s instruction for treatment.