Small amounts of gamma radiation used in medical treatment are not harmful to the human body. However, excessive gamma rays can cause damage to the human body’s blood system, immune system, central system and other systems. 1. Blood system: Excessive gamma rays can cause serious damage to the bone marrow, which is the blood-producing organ of the human body, resulting in the reduction of white blood cells, internal bleeding and other blood system manifestations, and the irradiated person may suffer from leukemia. 2. Immune system: As the bone marrow and hematopoietic system is seriously damaged, the immune function of the body will also be destroyed, which can lead to the dysfunction of various systems, resulting in serious complications and endangering the life. 3. Central system: When the central system is damaged, dizziness, spasm, tremor, consciousness disorder, activity disorder and so on can occur, which can lead to death in a short period of time. If the above symptoms appear, you should consult a doctor in time.