Last updated Feb. 15, 2022. Reviewed for accuracy on Dec. 11, 2019 by JoAnna Pendergrass, DVM
Benadryl is not yet FDA-approved for veterinary use, but it is generally considered safe for use in dogs with mild-to-moderate allergies. Benadryl is a brand name for an antihistamine (diphenhydramine HCl) that can help alleviate symptoms of allergic reactions and even anxiety. Histamine is a substance released by mast cells (a type of immune cell) and is responsible for inflammation and other allergy symptoms. The active ingredient in Benadryl is diphenhydramine, which works by blocking histamine receptors on a cell’s surface, meaning that the receptors cannot ‘accept’ histamine that tries to attach and trigger an allergic reaction.
Symptoms of allergic reactions that can be treated with Benadryl include hives, swelling, and itching. Severe reactions, like anaphylaxis, can be life-threatening and should be treated by a veterinarian (who may give an injection of diphenhydramine along with other emergency injections).
Many veterinarians approve Benadryl for home use as a regular go-to treatment. It may be suitable for:
How do I calculate the Benadryl dose for dogs in ml?
To calculate the liquid Benadryl (12.5 mg/5 ml) dose:
How Much Benadryl To Give a Dog?
A normal Benadryl dosage for dogs is between 0.9 to 1.8 milligrams of Benadryl for each pound of weight. For liquid Benadryl, you should use 0.4 ml per pound of weight.
You shouldn’t give them more than two to three doses a day.
Benadryl for Dogs Dosage by Weight — Comprehensive Chart
The right dose for your dog depends on its weight. For example, a 5 lb dog will need 5 mg of Benadryl, while a 15 lb dog will need 15 mg. Also, Benadryl tablets differ from liquid Benadryl, so dosages will be different.
To find the right Benadryl dose for dogs, check out our chart:
Also, be aware that measuring the best Benadryl dose for a dog is much easier with liquid Benadryl. Benadryl tablets contain 25 mg per tablet and might be a bit more difficult to dose.
If you have a small dog, using children’s Benadryl can help you get the right dosage more easily.
How much Benadryl can I give my 50lb dog?
How much Benadryl do you give a 70 pound dog?
According to the Merck Veterinary Manual, the safe dosage is 2-4 milligrams of medication per kilogram of weight, or 0.9 to 1.8 milligrams per pound. This amount can be administered two to three times daily, depending on your dog’s symptoms.
How many 25 ml Benadryl can I give my dog?
What happens if I give my dog too much Benadryl?