How much benadryl can you give a dog?

The standard dose is 1mg of diphenhydramine per pound of body weight, in 2 to 3 doses (every 8 to 12 hours). A dog that weighs 25lb would receive about 25mg per dose while a dog that weighs 50lb would receive about 50mg per dose. Always ask your vet first and do not exceed 3mg (per 24 hour period) per pound of body weight.

How much benadryl should you give a dog that weighs 50 lbs?

A dog that weighs 50 lb will need about 50 mg of diphenhydramine per dose. You can give two 25-mg tablets or 20 mL of a pediatric solution (12.5 mg/5 mL) every 8 to 12 hours.

Can You Give A Puppy Benadryl?

In general, it is not recommended to give Benadryl to puppies under 6 months of age without direct instruction from a veterinarian. As young dogs process medications differently than older dogs, you should always contact your vet before giving any medication to a young puppy.

What is a safe benadryl for dogs?

Only pure diphenhydramine. Avoid combination products (usually with a "D" on the label) as they may contain ingredients like pseudoephedrine or phenylephrine that are toxic to dogs. Also avoid products containing xylitol, acetaminophen, ibuprofen, or alcohol.

How fast does Benadryl work and how long do its effects last?

Benadryl usually begins to work within about 30 minutes and the effects last for about 8 to 12 hours. For this reason, it is usually taken two or three times a day.

What are some signs of an overdose of Benadryl in dogs?

An overdose of diphenhydramine can cause restlessness, increased heart rate, dilated pupils, dry mouth, difficulty urinating, unsteady gait and tremors. In severe cases, seizures or respiratory distress may also occur. If an overdose is suspected, contact a veterinarian or pet poison control hotline immediately for guidance on treatment.

Benadryl Dosage Calculator for Dogs

Your dog and the product

Dog's weight

Which Benadryl product?

Tablet — 25 mg (standard)

Children's liquid — 12.5 mg / 5 mL

Chewable / small tablet — 12.5 mg

Tablet — 50 mg (large dogs)

How often per day?

Twice a day (every 12 hours)

Three times a day (every 8 hours)

Any special considerations?

Single dose

Give this many 25 mg tablets

tablets

Give one dose every 12 hours (twice a day) as needed.

That is about 50 mg per day. Never give more than 75 mg (3 mg per pound) of diphenhydramine in 24 hours.

Use plain diphenhydramine only. Never give a combination product such as Benadryl-D or Allergy Plus Congestion — the decongestant (pseudoephedrine or phenylephrine) is toxic to dogs. Check the label for xylitol, acetaminophen, ibuprofen, or alcohol and do not use it if any are present.

This is a general starting guide. Always confirm the dose and that Benadryl is right for your dog with your veterinarian, especially for very large or giant breeds, pregnant dogs, or dogs on other medicines.

Single dose

Give 1 of a 25 mg tablet

twice a day — that is 25 mg of diphenhydramine per dose.

Total per day
Daily maximum

Dose in every form

The same weight-based dose (25 mg) in each Benadryl form
Product form	Amount for this single dose
Tablet (25 mg)	1 tablet(s)
Tablet (50 mg)	0.5 tablet(s)
Chewable / small tablet (12.5 mg)	2 tablet(s)
Children's liquid (12.5 mg / 5 mL)	10 mL

Every row delivers the same milligram dose — pick the form you have on hand. Scored tablets can be split; capsules and liqui-gels should not be opened or split. A children's liquid or a 12.5 mg tablet is easiest for small dogs.

This calculator will calculate the safe starting dose of Benadryl (the brand name for Diphenhydramine) based on your dog's weight. Enter the weight and select which product you want to use to show how many milligrams should be given, as well as the corresponding amount in tablets or liquid, dosing interval, and maximum daily dosage for your dog.

How much benadryl should i give my dog.

The usual veterinary dosage is one milligram of diphenhydramine per pound of body weight, or about 2.2 mg per kg. It is usually given two to three times daily, every eight to twelve hours.

\text{single dose (mg)} = \text{weight (lb)} \times 1

A 25 pound dog will need approximately 25 mg per dose, while a 50 pound dog will need approximately 50 mg per dose. The dosage is proportional to the body weight so there is no fixed upper limit like with human dosages. For very large or giant breed dogs you should have your veterinarian check the dosage.

Divide the milligrams by the strength of the product you are using to get an easier to measure amount.

\text{amount per dose} = \frac{\text{single dose (mg)}}{\text{product strength}}

Standard Benadryl tablets contain 25mg. The standard children's liquid contains 12.5mg per 5ml and therefore 2.5mg per ml. Gummies or mini-tablets contain 12.5mg. So a dose of 25mg would be one tablet with 25mg, 10ml of the children's liquid or two tablets with 12.5mg.

Benadryl dosage chart for dogs

The table below shows the single dose corresponding to each body weight as well as the amount for each dosage form. These values correspond with results given by a calculation tool.

Dog weight	Single dose	25 mg tablets	12.5 mg tablets	Liquid 12.5 mg/5 mL
5 lb	5 mg	under 1/4 tablet	under 1/2 tablet	2 mL
10 lb	10 mg	about 1/2 tablet	under 1 tablet	4 mL
20 lb	20 mg	about 3/4 tablet	under 2 tablets	8 mL
25 lb	25 mg	1 tablet	2 tablets	10 mL
40 lb	40 mg	about 1.5 tablets	about 3 tablets	16 mL
50 lb	50 mg	2 tablets	4 tablets	20 mL
80 lb	80 mg	about 3 tablets	not practical	32 mL

Dosage intervals and daily maximum dose

Benadryl is usually repeated every eight to twelve hours, which would be about two or three times a day. The medication's effects will normally last that long, so these intervals are optimal for when the effect wears off. The maximum daily dose for dogs is around 3 mg per pound of body weight and should be spread out in those doses.

The effect usually begins within 30 minutes. If a dog requires Benadryl daily and this lasts for more than one to two weeks, you should consult with a veterinarian to determine the cause and avoid long-term use without veterinary advice.

Your safety is our top priority.

Please give only pure diphenhydramine. Combination products are usually marked with the letter "D" in their name or sold under the brand name Allergy Plus Congestion and contain decongestants such as pseudoephedrine or phenylephrine, which are toxic to dogs. Also avoid any liquid or chewable products that list xylitol, acetaminophen, ibuprofen, or alcohol on the label.

Consult your vet before giving Benadryl to a puppy under six months old, brachycephalic breeds (dogs with short muzzles), or dogs with glaucoma, heart disease, high blood pressure, enlarged prostate, or epilepsy. Signs of an overdose include agitation, increased heart rate, dilated pupils, unsteady gait, and in severe cases seizures or respiratory depression.

If you suspect that your dog has overdosed on medication, contact a veterinarian immediately or the ASPCA Animal Poison Control Center or another pet poison helpline.

This calculator is for educational purposes only and does not replace veterinary advice. Dosage may vary in puppies, pregnant bitches, dogs with health problems or those on other medications. Always consult a vet before giving your dog medication.

Frequently asked questions

How much benadryl can you give a dog?: The standard dose is 1mg of diphenhydramine per pound of body weight, in 2 to 3 doses (every 8 to 12 hours). A dog that weighs 25lb would receive about 25mg per dose while a dog that weighs 50lb would receive about 50mg per dose. Always ask your vet first and do not exceed 3mg (per 24 hour period) per pound of body weight.
How much benadryl should you give a dog that weighs 50 lbs?: A dog that weighs 50 lb will need about 50 mg of diphenhydramine per dose. You can give two 25-mg tablets or 20 mL of a pediatric solution (12.5 mg/5 mL) every 8 to 12 hours.
Can You Give A Puppy Benadryl?: In general, it is not recommended to give Benadryl to puppies under 6 months of age without direct instruction from a veterinarian. As young dogs process medications differently than older dogs, you should always contact your vet before giving any medication to a young puppy.
What is a safe benadryl for dogs?: Only pure diphenhydramine. Avoid combination products (usually with a "D" on the label) as they may contain ingredients like pseudoephedrine or phenylephrine that are toxic to dogs. Also avoid products containing xylitol, acetaminophen, ibuprofen, or alcohol.
How fast does Benadryl work and how long do its effects last?: Benadryl usually begins to work within about 30 minutes and the effects last for about 8 to 12 hours. For this reason, it is usually taken two or three times a day.
What are some signs of an overdose of Benadryl in dogs?: An overdose of diphenhydramine can cause restlessness, increased heart rate, dilated pupils, dry mouth, difficulty urinating, unsteady gait and tremors. In severe cases, seizures or respiratory distress may also occur. If an overdose is suspected, contact a veterinarian or pet poison control hotline immediately for guidance on treatment.

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Disclaimer: This calculator is provided for general informational and educational purposes only. Our calculators are under active development, and results may be inaccurate, incomplete, or unsuitable for your situation. Always verify the figures independently and seek advice from a qualified professional before relying on them. We make no warranties and accept no liability for any loss or decision arising from use of this tool.

References

VCA Animal Hospitals: Diphenhydramine
Veterinary patient handout on diphenhydramine use, dosing, and cautions in pets.
Merck Veterinary Manual: Antihistamines used in animals
Professional reference on antihistamine pharmacology and dosing in animals.
ASPCA Animal Poison Control Center
Emergency guidance and 24/7 hotline for suspected poisonings and overdoses.
MedlinePlus (U.S. National Library of Medicine): Diphenhydramine
Authoritative drug information on diphenhydramine pharmacology and cautions.