In order to provide reference for the clinical diagnosis and treatment of vitamins and trace elements in patients with tumor⁃refractory cachexia, this article reviewed the metabolism and treatment of several vitamins and trace elements in patients with refractory cachexia through literature search. Studies have found that patients with tumor⁃refractory cachexia often have changes in the metabolism of vitamins or trace elements, such as Wernicke encephalopathy caused by vitamin B1 deficiency, vitamin B12 deficiency or functional vitamin B12 deficiency, vitamin C deficiency, clinical or subclinical vitamin K deficiency, low serum vitamin D level, iron deficiency anemia, and prolonged bleeding time caused by zinc deficiency, etc., these are caused by insufficient intake and/or reduced reserves, and abnormal metabolism caused by tumors. Vitamin B1 supplementation can effectively alleviate delirium caused by Wernicke encephalopathy, vitamin B12 supplementation can improve neurological dysfunction caused by vitamin B12 deficiency or functional deficiency, vitamin C supplementation can help improve the patient's overall condition and quality of life, and vitamin K supplementation can reduce the risk of bleeding caused by vitamin K deficiency or functional deficiency. When the patient's serum vitamin D level is low and accompanied by pain, vitamin D3 supplementation can be tried to reduce the dose of opioids. When the patient's ferritin is elevated but other parameters indicate the presence of iron deficiency anemia, iron replacement therapy can be tried, but it is necessary to closely monitor the adverse effects of iron on promoting tumor growth. When the coagulation function of patients with advanced tumors is only manifested as prolonged bleeding time, zinc supplementation can be tried. In short, patients with tumor refractory cachexia are high⁃risk groups of vitamin and trace element deficiencies. Patients with symptoms or suspected vitamin/trace element deficiencies should be diagnosed and treated.