The normal adult hemoglobin concentration is 120-160 g/L for men and 110-150 g/L for women. If it exceeds the normal range, the hemoglobin concentration is high. A common cause of high hemoglobin is a relative high. It is caused by the loss of water in the plasma, such as violent vomiting, extensive burns, severe diarrhea, and profuse sweating. High hemoglobin concentration occurs due to loss of water in the plasma and blood concentration. It is also seen in high hemoglobin concentration caused by hypoxia, such as inhabitants of highland areas, pulmonary heart disease in long-term hypoxia, cyanotic congenital heart disease, etc., and chronic obstructive pulmonary disease. In addition, hemoglobin concentration can also be high in blood system diseases, such as true erythrocytosis and primary thrombocytosis.