Diphenylpyraline hydrochloride is primarily used as an antihistamine to alleviate symptoms associated with allergic reactions, such as hay fever, hives, and other skin irritations. It works by blocking the effects of histamine, a substance in the body that causes allergic symptoms. This compound is often found in over-the-counter medications designed to treat itching, sneezing, and runny nose. Additionally, it may be included in multi-symptom cold and allergy formulations to provide relief from nasal congestion and other related discomforts. Its sedative properties also make it useful in certain sleep aids, helping to induce drowsiness in individuals struggling with insomnia.