Triprolidine hydrochloride is primarily used as an antihistamine to relieve symptoms associated with allergies, such as sneezing, runny nose, itchy eyes, and hives. It works by blocking the action of histamine, a substance in the body that causes allergic symptoms. This makes it effective in managing seasonal allergies, hay fever, and other allergic reactions. Additionally, it is often included in combination cold and flu medications to alleviate nasal congestion and improve breathing. Its sedative properties can also help reduce discomfort and promote rest in individuals suffering from allergy-related sleep disturbances.