Malnutrition is mostly caused by insufficient nutritional intake, digestion and absorption disorders, mainly manifested as weight loss, growth retardation, gastrointestinal discomfort, abnormal skin condition, abnormal mental state, low immunity and other symptoms: 1, weight loss: mild malnutrition when the weight change is not obvious, can be manifested as no weight growth; severe malnutrition patients with decreased body fat content, can appear in varying degrees of weight loss,. Most of them will have wasting performance. Compared with the same age, the same sex healthy people reference value, lower than the median weight; 2, growth retardation: in the growth stage of infants and children malnutrition can have obvious growth retardation performance, long-term nutritional intake or absorption and digestion dysfunction may make the bones, brain and other systems do not get sufficient nutrition and appear thin, muscle atrophy, mental retardation; 3, gastrointestinal discomfort. Some of them may have loss of appetite, partial eating, and nausea, vomiting, abdominal distension, diarrhea and other uncomfortable symptoms; 4, abnormal skin status: skin and hair dry, rough, some patients appear skin flaking, erythema, flaccidity and eyelid edema and other performance, hair is easy to break, nails have horizontal lines; 5, abnormal mental status: most of the patients with severe malnutrition usually have a hard time concentrating, but also have depression, memory 6, low immunity: the immune system to maintain normal function requires the body to provide sufficient protein and other nutrients, malnutrition makes the body susceptible to disease, such as during the change of season, susceptible to influenza, pneumonia, etc., manifested as fever, cough, cough and other respiratory tract infection symptoms.