You may have heard that you can give dogs Benadryl to treat allergies or bug bites. But is it safe? And will it really help your dog feel better?
Read on to learn when you should give your dog the antihistamine, how to figure out the best dosage, what side effects to watch for and more.
- Benadryl is usually safe for dogs and can alleviate some allergy symptoms, irritation from bug bites and anxiety.
- The correct Benadryl dosage is 2 to 4 milligrams per kilogram of your dog's weight.
- It's best to consult with a veterinarian before giving your dog any medication, including Benadryl.
What Is Benadryl?
Benadryl, known generically as diphenhydramine, is a popular antihistamine. It blocks receptors for histamines, which cause allergic reaction symptoms.
In humans, it reduces such symptoms as irritation in the eyes, runny nose and sneezing. People often take it to mitigate allergic conditions like hay fever or for the common cold.
Although the Food and Drug Administration has not approved Benadryl for dogs, many veterinarians recommend it for some conditions. Its effects on dogs are well documented in veterinary manuals and research, going as far back as 1950.
When to Give Your Dog Benadryl
Just like in humans, Benadryl is best for treating mild or moderate symptoms of allergic reactions. Vets may recommend it for several conditions:
- Symptoms from airborne allergens. Dogs, like humans, are sometimes allergic to things like pollen. They may experience watery eyes, sneezing, coughing or irritated skin. Benadryl can help with those symptoms.
- Symptoms of food allergies. Some dogs have food allergies, causing symptoms like irritated skin, vomiting or diarrhea. Benadryl can reduce these symptoms while you search for food better suited to your dog.
- Symptoms of skin allergies. Dogs can have allergic reactions from contact with things like food, chemicals in the environment and fleas. Benadryl can mitigate symptoms like irritation and paw licking while you address the root cause.
- Managing allergic reactions to bug bites or stings. Dogs can sometimes stick their noses where they don't belong, including beehives and ant nests. Benadryl may reduce some of the swelling and irritation from an insect encounter, but you should see a vet if symptoms get serious.
- Reducing anxiety. Benadryl can help manage anxiety and promote relaxation in dogs. This is because one of its side effects is drowsiness. However, hyperactivity is another possible side effect, so Benadryl may not reduce anxiety in your pet.
Remember that Benadryl is not made for dogs. It is not guaranteed to work every time on every dog. If mild and moderate symptoms in your dog don't improve after taking Benadryl, speak to your veterinarian about treatment options.
If your dog is having a severe allergic reaction, such as having difficulty breathing, Benadryl will not fix it. Take your pet immediately to an emergency vet.
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Benadryl Dosage for Dogs
The Merck Veterinary Manual recommends giving dogs 2 to 4 milligrams of Benadryl per kilogram of weight. That's 0.9 to 1.8 milligrams per pound. Give the dosage every six to eight hours as needed.
To find the appropriate dosage for your dog, multiply its weight in pounds by 0.9. If you don't see results, you can work your way up to the maximum dosage—your dog's weight times 1.8. But it's safest to start at the lowest recommended dose in case your dog experiences side effects.
You can also find your dog's weight on our charts and look for the appropriate dosage range:
Benadryl Dosage Chart for Dogs (Tablets)
Benadryl often comes in 25 or 50 mg tablets. You may need to cut the tablet to get the right dosage for your dog.
| Dog Weight (lbs) | Benadryl Dosage (mg) |
| 10 lbs | 9 to 18 mg |
| 20 lbs | 18 to 36 mg |
| 30 lbs | 27 to 54 mg |
| 40 lbs | 36 to 72 mg |
| 50 lbs | 45 to 90 mg |
| 60 lbs | 54 to 108 mg |
| 70 lbs | 63 to 126 mg |
| 80 lbs | 72 to 144 mg |
| 90 lbs | 81 to 162 mg |
| 100 lbs | 90 to 180 mg |
Benadryl Dosage Chart for Dogs (Liquid)
Benadryl also comes in liquid form.
Liquid dosage is calculated slightly differently. Divide your dog's weight by four to find the right liquid Benadryl dosage in milliliters.
Use a dropper to measure the correct dosage for your dog.
| Dog Weight (lbs) | Benadryl Dosage (mL) |
| 10 lbs | 4 mL |
| 20 lbs | 8 mL |
| 30 lbs | 12 mL |
| 40 lbs | 16 mL |
| 50 lbs | 20 mL |
| 60 lbs | 24 mL |
| 70 lbs | 28 mL |
| 80 lbs | 32 mL |
| 90 lbs | 36 mL |
| 100 lbs | 40 mL |
Is Benadryl Safe for Dogs?
In most cases, Benadryl is safe for dogs. But it is not safe for dogs with certain medical conditions, including:
- Glaucoma
- High blood pressure
- Cardiovascular disease
Additionally, Benadryl is sometimes mixed with other medications, like Tylenol. Before giving your dog any Benadryl, make sure that diphenhydramine is listed as the only active ingredient.
You should always consult a vet before giving your dog any medication, including Benadryl.
Can Dogs Overdose on Benadryl?
Yes. Dogs can overdose on Benadryl if they take more than the maximum amount within a six- to eight-hour time frame.
The Merck Manual recommends watching for these signs of Benadryl overdoses:
- Depression
- Hyperactivity
- Drooling
- Rapid breathing
- Rapid heartbeat
- Upset stomach
- Lack of coordination
- Tremors
- Fever
- Seizures
Overdose symptoms usually show up within one hour of Benadryl exposure, but you should always be mindful of your dog's condition while it is on the drug.
Potential Benadryl Side Effects in Dogs
According to the Merck Manual, common Benadryl side effects in dogs include:
- Depression
- Hyperactivity
- Drooling
- Rapid breathing
- Rapid heartbeat
These are also some of the symptoms of overdosing on Benadryl. You should always consult with a vet if your dog shows side effects from taking the drug.
Benadryl for Dogs FAQ
It's natural to have questions before you give your dog medication. If you have a question that isn't covered here, talk to your vet before administering Benadryl to your dog.
How Often Can I Give My Dog Benadryl?
The Merck Manual recommends giving your dog Benadryl every six to eight hours as needed. Stick to this schedule by giving your dog the recommended dose in the morning, early afternoon and evening.
How Do I Get My Dog to Take Benadryl?
Medication usually tastes bad, so dogs will avoid taking it. They don't understand that it's good for them.
Some tactics to get your dog to take Benadryl tablets include:
- Hiding a tablet in its food. Dogs might not notice their medication if they eat quickly. This works best with soft and wet food that you can mold around the pill. That includes dog-safe peanut butter.
- Placing the pill on the back of your dog's tongue and closing its mouth, as the Cornell University College of Veterinary Medicine recommends.
- Take your dog to the vet. Veterinarians will sometimes administer medication on your behalf. They're experts at it, and this is a good solution if your dog doesn't need medication often.
Can I Give Benadryl to My Puppy?
Yes. Just make sure you give it the appropriate dosage for its weight.
As with any dog, consult with a vet before giving Benadryl to your puppy.
Can I Use Benadryl to Help My Dog Sleep?
Drowsiness is a possible side effect of Benadryl, but vets don't usually recommend it as a sleep aid.
If you're concerned about your dog's sleeping habits, it's better to consult with a vet rather than giving it Benadryl to help it sleep. You can also ask your vet if giving your dog melatonin is an option.
Should I Give My Dog Regular or Children's Benadryl?
You can use either regular or children's Benadryl as long as you follow the recommended dosage for your dog's weight.
Whatever type of Benadryl you use, make sure that diphenhydramine is the only active ingredient.
Benadryl is usually safe and helpful for treating periodic allergies in dogs, like hay fever. But be careful of the dosage and watch for side effects.
Remember that Benadryl treats only symptoms. Don't forget to address the underlying problems so you can take your dog off the drug.
Learn more about dealing with other common dog illnesses so you're prepared the next time your furry friend isn't feeling well.
