High blood creatinine with no appetite is mainly caused by the stimulation of the gastrointestinal tract by creatinine and other toxins, and in severe cases, it may cause erosion or ulceration of the gastric mucosa and gastrointestinal bleeding. Elevated blood creatinine can be seen in chronic kidney disease and acute renal failure, both may appear gastrointestinal symptoms such as no appetite, acid reflux, nausea, vomiting, abdominal distension. Chronic kidney disease is the end result of all kinds of kidney disease, can be divided into 5 stages, the main manifestations are creatinine, urea nitrogen elevation, anemia, calcium and phosphorus disorders, metabolic acidosis, shrinkage of the kidneys and so on. Stages 1 to 3 may only have symptoms such as fatigue, lumbago, nocturia, etc. After stage 3, the symptoms manifest differently and can be seen in all systems, digestive system such as decreased appetite, nausea, vomiting; respiratory system can be seen in shortness of breath, shortness of breath; cardiovascular system can be seen in high blood pressure, respiratory distress and so on. Acute renal failure refers to the clinical syndrome caused by various triggers such as gastrointestinal bleeding, cardiac insufficiency, urinary tract obstruction, etc., resulting in a sudden or sustained decline in the glomerular filtration rate, causing nitrogen waste storage, water, electrolyte and acid-base balance disorders, leading to complications in various systems. Involvement of the digestive system can be manifested as gastrointestinal discomfort, such as poor appetite. For patients with elevated creatinine and loss of appetite, it is recommended to go to nephrology department of regular hospitals for diagnosis and treatment after comprehensive evaluation by specialized doctors.