Zyncet syrup is an over-the-counter medication containing the active ingredient cetirizine. It is commonly used to relieve allergy symptoms such as sneezing, runny nose, itchy or watery eyes, and itching of the throat or nose. This antihistamine works by blocking the action of histamine, a substance in the body that causes allergy symptoms. Zyncet syrup should be taken as directed by a healthcare provider for effective allergy relief.