The adverse reactions of chlorpheniramine include drowsiness, dizziness, headache, dry mouth, nausea, vomiting, hypotension, etc., which can easily excite the central nervous system and induce epilepsy. Long-term application can cause granulocytopenia. Therefore, it is forbidden for epileptic patients, infants and lactating women, and is very useful for patients with pyloric obstruction, prostatic hypertrophy, bladder neck obstruction, narrow-angle glaucoma, hyperthyroidism and hypertension.