Medically reviewed by Daniel Combs, MD Benadryl (diphenhydramine) is an over-the-counter (OTC) antihistamine commonly used to ...

Use only plain diphenhydramine and avoid formulas with decongestants or alcohol. The correct dosage depends on your dog's weight. Monitor for side effects, and contact your vet immediately if you ...

Related: Benadryl for Dogs: Side Effects of Long-Term Use At normal doses, Benadryl is quite safe, but a survey of over 600 dogs (1) found the following signs of overdose: Three of the dogs in ...