The drug paracetamol is a member of the class of drugs known as analgesics, which relieve pain, and antipyretics, which lower fever. Pseudoephedrine hydrochloride is a drug that reduces nasal stuffiness that you may experience during colds and the flu. It is a member of the class of medications known as "decongestants." As an antihistamine, diphenhydramine hydrochloride helps ease the symptoms of allergies, colds, and the flu, including sneezing, coughing, runny nose, itching, watery eyes, and itchy eyes and throat. If discomfort prevents you from getting a good night's sleep, diphenhydramine can also aid. Cold and flu-related symptoms, such as sore throat, cough, fever, headache, runny nose, muscle aches, and stuffy and clogged nose, can be quickly relieved with this combination.