The main functions of Difenidol Hydrochloride are to improve cerebral circulation, anti-vertigo, regulate the vestibular system, and stop vomiting, and it is mainly used for the treatment of vertigo caused by various reasons. Difenidol Hydrochloride can improve cerebral circulation, especially in the region of the vertebrobasilar artery; it can also regulate the vestibular system to play the role of anti-vertigo and antiemetic. The vertebrobasilar system supplies blood to the brainstem and cerebellum, which are closely related to vertigo. If they are ischemic, symptoms of vertigo will occur. Difenidol Hydrochloride tablets can be used for all causes of vertigo, as well as for the prevention of motion sickness and seasickness. Taking it half an hour before traveling in a car or on a boat can help prevent vertigo. This medicine may have adverse effects of dizziness, drowsiness, panic, and headache. It should be used with caution in patients with glaucoma and stomach ulcers. Patients with renal insufficiency are prohibited from using this medicine.