Frequent belching after chemotherapy for lung cancer may be caused by drug side effects, phrenic nerve injury or irritation, improper diet and so on. 1. Drug side effect: some chemotherapy drugs have the side effect of affecting digestive function, which may lead to digestive tract function disorder and belching after use. 2. Phrenic nerve injury or stimulation: when chemotherapy stimulates or damages the phrenic nerve, it may cause abnormal spasm of the diaphragm and lead to frequent belching. 3. Improper diet: Eating raw and cold fruits and vegetables, stimulating food after chemotherapy may cause related digestive symptoms and belching. If frequent belching occurs after chemotherapy for lung cancer, one can communicate with the treating physician in time to change the treatment plan or adjust the dosage of relevant drugs, or take other drugs to treat the corresponding symptoms.