Used primarily as an antihistamine to relieve symptoms of allergies, such as sneezing, runny nose, itching, and skin rashes. It is also effective for treating motion sickness, vertigo, and associated nausea and vomiting due to its anticholinergic effects. Due to its sedative properties, chlorcyclizine is utilized in some formulations to promote sleep or manage mild anxiety. It may additionally suppress chronic cough from respiratory irritation by depressing the cough center. Chlorcyclizine has been investigated for potential antiviral activity against enveloped viruses through interference with membrane fusion processes. Its use in over-the-counter cold and allergy preparations is limited compared to newer antihistamines because of higher drowsiness incidence; medical supervision is recommended.