Benadryl Allergy Children's 6+ 1mg/1ml Oral Solution treats children aged 6 years and over and adults: Suffering from hay fever and year round allergies such as dust or pet allergies. It can also be used to treat the symptoms of urticaria, also known as hives. This medicine contains cetirizine dihydrochloride which is an antihistamine that helps relieve allergy symptoms associated with the above conditions, such as sneezing, runny nose, watery eyes and skin rashes.