Nov 29, 2018 Use these benadryl dosage guides for infants and children younger than 12 years old. Children 2 years to 5 years, DO NOT USE unless directed by a doctor. Childen 6 years to 11 years, 5 mL to 10 Children;s BENADRYL Chewable Tablets (diphenhydramine hydrochloride 12.5 mg). Find the...