St. Louis Children;s Hospital provides a Diphenhydramine (Benadryl - Allergy Medicine) Dosage Table for determining the amount of allergy Chewable 12.5 mg, --, 1, 1½, 2, 4, tablets It should not be given if under 4 years old. If not, you can get a med syringe at drug stores. Author: Barton D....