Zyrtec 10mg Tablets 30’s contain Cetirizine. Cetirizine is an antihistamine that relieves allergy symptoms. It works by blocking a specific natural substance (histamine) that your body makes during an allergic reaction.

How to take it. Adults and children 6 years and older can take cetirizine capsules and tablets. The usual dosage for adults younger than 65 years and children who are 6 years and older is one 10-milligram (mg) dose per day. You shouldn’t take more than 10 mg in 24 hours.