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How much Benadryl is safe for dogs

Health & Wellness

How much Benadryl is safe for dogs?

Ask your vet about the serving size

With your vet’s guidance, Benadryl’s drowsy side effect may help stop your dog from excessive scratching during an allergic reaction to a bug bite or vaccination. However, the amount of Benadryl you give your dog determines how successful it is. Veterinarian and pet health advocate Dr. Aliya McCullough explains how to serve your dog a safe amount of Benadryl. 

How often can you give a dog Benadryl? 

Always talk to your vet before introducing your dog to new medication. The amount of Benadryl you give your dog depends on your dog’s weight and health status.

Call your vet or poison control immediately if you think your dog got into Benadryl while you weren’t around. Having a pet emergency preparedness plan in place in case this ever happens can be helpful, too. Some quick steps to get you started are:

  • Write down the phone numbers for poison control, local 24-hour emergency pet hospitals and animal ambulances in your area.
  • Put together a pet emergency kit including latex gloves, an information card with your vet’s address and phone number and towels. 
  • Practice for emergencies by familiarizing your pet with riding in the car.

Dog Benadryl dosage chart

Talk to your veterinarian about determining the right amount of Benadryl for your dog. High doses of Benadryl can cause dry mouth, difficulty urinating and constipation. If you think your dog is overdosing on Benadryl, contact poison control or get to your emergency animal clinic as soon as possible. These are the key signs that your dog had too much Benadryl:

  • Tremors
  • Sedation and depression (more common in older dogs)
  • Hyperactivity (typically affects younger pups)
  • Anxiety
  • Aggression
  • Incoordination
  • Seizures
  • Coma
  • Vomiting
  • Diarrhea
Can you give a dog Tylenol, Benadryl or ibuprofen


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Liquid Benadryl dosage for dogs

Avoid liquid Benadryl as it can contain sodium or alcohol. Liquid Benadryl is also harder to administer, which can make your pup feel sick. Contact your vet if your dog starts showing signs of illness like:

  • Nausea
  • Vomiting
  • Incoordination
  • Disorientation
  • Coma
  • Seizures
  • Tremors
  • Blindness

When to avoid giving your dog Benadryl

Dogs shouldn’t take Benadryl if they’re allergic (or currently doing allergy testing), pregnant or suffer from asthma, glaucoma, seizures or prostate or urinary disease.

When used safely, Benadryl can prevent your dog from scratching during an allergic reaction — just make sure to talk to your vet and follow our tips before treating your pet. 

Photo by Michael Oxendine on Unsplash

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