Clarityn allergy 10mg tablets belong to a group of medicines known as antihistamines. Antihistamines help to reduce allergic symptoms by preventing the effects of a substance called histamine, which is produced in the body. The tablet relieves symptoms associated with allergic rhinitis (eg hayfever) such as sneezing, runny or itchy nose & burning or itching eyes. The tablet may also be used to help relieve symptoms of urticaria (itching & redness), which is often known as hives or nettle rash.