During radiotherapy, some normal tissues are inevitably exposed to radiation and produce corresponding radiation reactions and damage. Generally speaking, timely adjustment of the treatment plan and the application of some Chinese and Western drugs can often reduce and prevent these reactions, so that radiotherapy can continue. However, it is not uncommon to interrupt the treatment or cause obvious radiation damage and sequelae because of too much reaction to radiation therapy. The possible reactions include: 1. Systemic reactions: related to the size of the irradiated field at the treatment site and the dose of each irradiation. The main manifestations are nausea, anorexia, vomiting, headache and general fatigue and indigestion. It may occur 1 to several hours or 1 to 2 days after radiotherapy. The treatment method is to adjust the treatment method and dose in time; give vitamin B, take sufficient water, use sedative or give Chinese medicine treatment if necessary. 2.Blood reaction: Since bone marrow and lymphoid tissue are highly sensitive to radiation, radiotherapy can lead to a decrease in white blood cells and platelets. The degree of decrease is related to the irradiation range and whether chemotherapy drugs are applied before and during radiotherapy. In order to prevent such complications, doctors mostly use blood cell-raising drugs, such as blood lysine, inosine, shark’s liver alcohol and Chinese herbal medicines to support Yin, nourish blood and benefit Qi during radiotherapy. 3.Local reaction: The tolerance of tissues in different parts of the body to radiation is different. With the increase of radiation dose, normal tissues or organs can show three stages of transient radiation reaction, early radiation damage and late radiation damage. Generally speaking, the transient radiation reaction and early radiation damage can be recovered, but the possibility of recovering from late radiation damage caused by excessive radiation is relatively small.