- Not a substitute for professional veterinary help.
When you have sniffles and seasonal allergies, you might take an antihistamine like Benadryl—and experts say you can also give Benadryl to your dog.
Benadryl can be helpful if your dog has a history of allergic reactions, anxiety, itchiness, or other conditions, says Whitney Miller, DVM, Chief Veterinarian at Petco.
Not every type of Benadryl is safe for dogs, though. That’s one reason why you should always talk to a vet before giving your pup Benadryl, or any medication.
Below, learn when to give your dog Benadryl and how to do it safely.
When Can You Give A Dog Benadryl?
Dr. Miller says Benadryl may offer your dog some relief from the following issues.
Allergies
Benadryl is an antihistamine, meaning it blocks histamine receptors. Histamines are inflammatory chemicals associated with seasonal allergy symptoms like congestion and sneezing.
“The medication can be a big help in relieving symptoms like itching, swelling, and pain,” Dr. Miller says.
Anxiety
Benadryl can cause drowsiness in both people and dogs. If you need to keep your dog calm for a stressful event, like a firework-filled New Year’s Eve or a long car ride, the medication could act as a mild sedative.
Insect bites or bee stings
Did your dog lose a battle with a wasp? Some vets may suggest Benadryl as a way ease the reaction from bee and wasp stings or insect bites.
Nausea
Benadryl can act as an anti-nausea medication, making it a potential treatment for motion sickness. In other words, it could be a dog’s best friend if they get sick on car rides.
Skin reactions
According to Dr. Miller, topical Benadryl could offer relief from allergic skin reactions and potentially soothe issues like hives.
Mast-cell tumors
Some vets may prescribe diphenhydramine (the generic for Benadryl) as a treatment for mast-cell tumors (MCTs).
MCTs grow on the mast cells, which are cells in the connective tissues that carry histamine.
Benadryl Dosages For Dogs
Dr. Miller says the exact dosage for Benadryl will vary from dog to dog, but that it’s a good rule of thumb to give one milligram (mg) per pound of your dog’s body weight.
Some evidence suggests it’s safe to give dogs anywhere from 2-4 mg of Benadryl per pound of weight.
The chart below shows possible dosages for dogs of different sizes. But again, always ask your vet about the right dosage for your pup.
Dog Weight | Benadryl Dose |
10 pounds | 10-40mg |
25 pounds | 25-100mg |
50 pounds | 50-200mg |
100 pounds | 100-400mg |
What Kind Of Benadryl Should You Give Your Dog?
Since Benadryl is a name-brand medication meant for people, it’s important to look at the label carefully before giving it to your pup. Dr. Miller says that dogs should only take plain Benadryl, or diphenhydramine.
Some Benadryl products may contain ingredients that aren’t safe for your dog, like alcohol or decongestants. Read the label carefully and avoid giving your dog Benadryl with these ingredients.
Name-brand Benadryl is available in a few different forms, each with its own pros and cons.
Benadryl tablets or pills
You can typically find Benadryl tablets in 10, 12.5, 30, and 50 mg doses, which may be appropriate for small to large dogs.
Benadryl capsules come in 25 mg and 50 mg doses. Their small size makes them perfect for tucking into pill pouches or hiding inside treats. However, the dosages may be too large for small or toy breeds.
Liquid Benadryl
If your dog is too small for a Benadryl tablet or capsule, liquid Benadryl may work better. You can customize the exact dosage and then give your dog the liquid medication in a dropper or syringe.
Topical Benadryl
“For allergies that affect the skin, there’s also a Benadryl spray and ointment available that can help provide relief,” Dr. Miller says.
Before using topical Benadryl on your dog, make sure all of the ingredients are dog-friendly. Always read the label for instructions before applying it to your dog’s skin.
Can Benadryl Cause Side Effects In Dogs?
Some dogs will experience side effects after taking Benadryl. According to Dr. Miller, the most common side effects are drowsiness and dry mouth. These will usually occur within the first few hours after your dog takes the medication.
Dr. Miller also says that while Benadryl may help ease anxiety for some dogs, it may have the opposite effect on others and make them more anxious.
So, if you plan to use Benadryl to help your dog manage anxiety around a specific event, like a plane ride, Dr. Miller suggests doing a trial run to test their reaction first.
Signs Of A Benadryl Overdose
In rare cases, dogs can overdose on Benadryl, and an overdose may be fatal. However, Dr. Miller says Benadryl overdoses are usually treatable with quick vet intervention.
Take your dog to the vet immediately if they experience any of these severe side effects:
- Abnormal heart rate
- Vomiting
- Tremors
- Seizures
Human medications account for 17% of all calls made to the ASPCA’s pet poison hotline. So, to keep your pup from getting into the Benadryl, store it in a sealed container in a secure spot where they can’t reach it—and always check with your vet to make sure you give your dog the right dose for their size.
You’ll also want to ask your vet before giving any new medication to your dog.