Total cholesterol is the sum of cholesterol contained in all lipoproteins in the blood, including free cholesterol and cholesteryl esters. In addition to food intake, cholesterol is also synthesized in the body. The liver and small intestine provide about 90% of endogenous cholesterol in adults, and total cholesterol levels are usually influenced by various factors such as age, gender, food, and mental health. The causes of low total cholesterol include disease factors and non-disease factors, including hypolipoproteinemia, hyperthyroidism, cirrhosis, acute severe hepatitis, anemia, and malignancy. Non-disease factors include poor nutrition, such as long-term vegetarianism, partial diet, and taking certain medications, such as estrogen, thyroid hormone, and lipid-lowering drugs, which can lead to low total cholesterol. The treatment of different diseases that cause low total cholesterol cannot be generalized, and different treatments are needed according to the specific diseases, mainly including general treatment, medication, radiotherapy, surgery, etc. After treatment, regular follow-ups are needed according to the actual situation. In terms of diet, we need to pay attention to a balanced diet and nutrition, avoid eating too much fried, barbecued and other unhealthy foods, and eat more fresh fruits and vegetables on a daily basis.