Decreased blood creatinine is seen in hypometabolism and malnutrition, and treatment is mainly to increase nutrition. Blood creatinine is divided into endogenous creatinine and exogenous creatinine according to its source. Endogenous creatinine refers to the metabolic products of the tissues in the body, whereas exogenous creatinine refers mainly to the products of the metabolism of meat foods in the body. Such as the elderly, excessive weight loss, due to reduced intake, low muscle content metabolism slow, so there will be a decrease in blood creatinine. Patients with decreased blood creatinine should supplement their nutrition in time and increase their protein intake, such as lean meat, eggs and milk. People with decreased blood creatinine should go to the nephrology department of the hospital in time and adjust their diet under the guidance of doctors.