Toxic side effects of targeted drugs mainly include; first, allergic reactions, mostly seen in monoclonal antibody-based targeted drugs, such as Merova, Epiduo and so on, appearing when patients first use them and relieving after stopping or reducing the drug. Second, skin toxicity is the most common toxic side effect of targeted drugs. It is mainly manifested as nail changes, nail fungus, mouth ulcers, rash, etc. Third, gastrointestinal toxicity, diarrhea, vomiting, and in severe cases, dehydration, and some patients may experience abdominal pain, abdominal distention, and reduced appetite. Fourth, cardiac toxicity, manifested as hypertension, myocardial ischemia, myocardial infarction, and decreased left ventricular ejection fraction. Fifth, pulmonary toxicity, mainly including subacute pneumonia, acute pneumonia, pulmonary hemorrhage, pulmonary hypertension, etc.. The most representative drugs are such as Eretzac and Troche, which are prone to pulmonary toxicity.