It is used to prevent vertigo, nausea and vomiting caused by various reasons or diseases, such as motion sickness when riding in cars, boats and airplanes, etc. Its active ingredient, diphenhydramine hydrochloride, is a strong anti-dizziness and anti-emetic drug, with stronger effect than chlorpromazine in inhibiting vomiting caused by apomorphine and stronger effect than theophylline in inhibiting nystagmus caused by hot and cold stimulation, and no drowsiness effect. Clinical practice has shown that it is effective for vertigo and vomiting caused by various reasons, especially for vertigo and vomiting caused by inner ear vestibule and vagus. Common adverse reactions of this drug include dry mouth, palpitations, dizziness, headache, drowsiness, restlessness and mild gastrointestinal discomfort, occasional hallucinations, hallucinations, disorientation, neurosis, depression, etc. If overdose or serious adverse reactions occur, immediate medical attention should be sought.