Antiflu is a medicine used to treat hay fever, sinusitis, and cold symptoms such as headache, muscle aches, fever, runny nose, upper respiratory tract obstruction, and eye pain, which are symptoms associated with upper respiratory allergies. Antiflu has analgesic, antipyretic, anti-inflammatory, antihistamine, anticholinergic, antitumor, and anticonvulsant properties, and works by constricting blood vessels in the body.