1.Infection Due to leukemia causes normal white blood cell reduction, especially neutrophil reduction, at the same time, chemotherapy and other factors also lead to the lack of granulocytes, so that patients are prone to serious infection or sepsis. Bacteria causing infections include Gram-positive bacteria such as Staphylococcus aureus, Streptococcus hemolyticus, and Corynebacterium; Gram-negative bacteria such as Pseudomonas aeruginosa, Escherichia coli, and Klebsiella. Mycobacterial infections such as Candida albicans, Aspergillus, Trichoderma, Trichoderma expansum, etc. The above mentioned mycobacterial infections occur most often in patients with prolonged agranulocytosis or persistent fever who are not susceptible to antibiotics. Some patients receiving corticosteroid therapy are more susceptible to viral infections such as varicella zoster virus and herpes simplex virus due to low cellular immunity. In addition, Pneumocystis carinii infection is also common, and upper respiratory tract infection and pneumonia are its common types. 2, intestinal failure Due to the treatment of leukemia in the chemotherapy drugs, radiotherapy means to affect the gastrointestinal function, and lead to intestinal failure. Nutritional supplementation of patients becomes a prominent problem, and the current use of subclavian vein cannulation into the superior vena cava for high nutritional infusion only partially solves the problem. Nutritional deficiencies can occur with complications such as pneumonia and enteritis. 3.Hyperuricemia Normal people due to the metabolic decomposition of nucleic acid, daily urinary excretion of uric acid 300 to 500 mg. leukemia patients due to the decomposition of nucleic acid in a large number of leukemia cells can increase the amount of uric acid excretion dozens of times. When the patient receives chemotherapy, radiotherapy and other treatments, hyperuricemia occurs, the application of corticosteroids and so on can increase the hyperuricemia, high concentration of uric acid quickly oversaturation and precipitation, causing extensive damage to the renal tubules and uric acid stones, which can lead to oliguria, anuria. Therefore, leukemia patients must be supplemented with more adequate fluids to ensure a certain amount of urine, and take allopurinol, such as the occurrence of renal failure must limit the amount of rehydration, and dialysis treatment. 4, lung disease due to leukemia patients with normal mature neutrophil reduction, reduced immune function, often leading to lung infection. In addition, the infiltration of leukemia cells can block the small blood vessels and bronchial tubes in the lungs, which may lead to dyspnea and respiratory distress syndrome. Chest X-ray can have hairy glass or corn grain net shape, which can be used as experimental treatment of lung radiation. 5, electrolyte imbalance leukemia treatment process is often due to excessive destruction of white blood cells, or due to chemotherapy leading to renal damage, and then discharge too much potassium. Chemotherapy patients have poor appetite, which leads to dysfunction of the digestive system, and insufficient incorporation leads to hypokalemia. Cell destruction increases phosphorus release, resulting in low calcium. Therefore, attention should be paid to the electrolyte concentration of potassium, calcium and sodium in the course of treatment. 6.Disseminated intravascular coagulation (DIC) A group of serious bleeding syndromes.