Compare to Benadryl® Allergy Ultratab™ active ingredient^ Drug Facts: Kirkland Signature™ Allergy Medicine, antihistamine and allergy relief. Active Ingredients (in each tablet) - Purpose: Diphenhydramine HCl 25 mg - Antihistamine Inactive Ingredients: Corn Starch, D&C Red #27 Aluminum Lake, Dicalcium Phosphate, Magnesium Stearate, Microcrystalline Cellulose, Polyethylene Glycol, Polyvinyl Alcohol, Silicon Dioxide, Stearic Acid, Talc, Titanium Dioxide. Uses: Temporarily relieves symptoms from hay fever and upper respiratory allergies: