Low hemoglobin and tumor may have some relationship with the degree of benign and malignant tumor and growth site. 1. Benign tumors refer to tumors without infiltration and metastasis, slow growth, benign tumors of digestive system such as esophageal smooth muscle tumor, hemangioma, etc. may have blood in vomit and black stool, benign tumors of urinary system such as renal papillary adenoma may cause blood in urine and other symptoms, which may cause low hemoglobin. Other benign tumors such as renal cysts, liver cysts, intestinal polyps, etc. generally have little effect on hemoglobin. 2. Malignant tumors can invade blood vessels or rupture small blood vessels of cancerous tissues and bleed, such as lung cancer can cause hemoptysis, gastric cancer, esophageal cancer can vomit blood or have blood in the stool, and rupture of liver cancer can cause intra-abdominal hemorrhage and so on, which can cause low hemoglobin. However, not all malignant tumors will cause low hemoglobin, but can also show normal or high hemoglobin. Leukemia belongs to hematologic malignancies, which can cause low hemoglobin due to abnormal bone marrow hematopoiesis. Some chemotherapeutic drugs can have side effects of bone marrow suppression during treatment, causing low hemoglobin. When low hemoglobin is found, the examination should be completed in time, and the cause of the disease should be identified, and the treatment should be standardized under the guidance of the doctor.