The protocol in brief
The dose on this page is the standard protocol published in ASPCA Animal Poison Control guidance for inducing vomiting in dogs at home when a professional has advised it. The rule has three parts, and all three matter. First, the rate: 1 teaspoon of 3 percent hydrogen peroxide per 5 lb of body weight. Because a teaspoon is 5 mL, that rate is the same as 1 mL per lb, which is the form this calculator uses. A 10 lb dog therefore receives 10 mL, a 20 lb dog receives 20 mL, and a 40 lb dog receives 40 mL. Second, the concentration: only the familiar 3 percent household solution is used. Stronger products, including hair developer strengths and industrial or food grade concentrates, are never used, because they can burn the mouth, throat and stomach lining and can cause serious injury out of proportion to any benefit. Third, the cap: the dose stops rising at 3 tablespoons, which is 45 mL, however heavy the dog is. A 45 lb dog reaches the cap exactly, and a 60 lb, 80 lb or 100 lb dog still receives 45 mL, not 60, 80 or 100 mL. Giving more does not make vomiting more likely in a safe way; it raises the risk of side effects such as prolonged vomiting, stomach irritation and aspiration.
The phone call comes first, every time
Hydrogen peroxide is not a first response you decide on alone. Whether vomiting should be induced at all depends on what was swallowed, how much, how long ago, and the health of the individual dog, and some poisonings are made worse, not better, by vomiting. That judgement belongs to a veterinarian or to a poison control specialist who handles these cases every day. Call your veterinarian or ASPCA Animal Poison Control on (888) 426-4435 first, describe exactly what the dog ate, the amount if you know it, the time it happened, and the dog breed, weight and any existing health problems. Follow the advice you are given, even if it differs from using this calculator: the professional on the phone may tell you to bring the dog in instead, to watch and wait, or to give the dose exactly as calculated here. Keep the packaging of whatever was swallowed, because the label details help the adviser identify the risk. If the dog later needs to be seen, bring the packaging and a sample of any vomit if you can do so safely. Time matters as well: inducing vomiting is most useful within 2 hours of ingestion, before the material has moved out of the stomach, so make the call as soon as you discover the problem rather than searching for information first.
Dogs only, and never cats
This protocol applies to dogs only. Hydrogen peroxide must never be given to cats to make them vomit. Cats respond differently, home induction in cats is unreliable and can cause significant harm, and there is no cat dose on this page because there is no safe home version of this protocol for cats. The same caution applies to other pets: do not transfer a dog dose to a rabbit, a ferret or any other animal by scaling the weight. If a cat or any other animal has swallowed something harmful, the correct action is the same first step as for a dog, a call to your veterinarian or to ASPCA Animal Poison Control on (888) 426-4435, but the treatment from that point is the professional decision, and for cats it usually means a veterinary visit where vomiting, if it is appropriate at all, is induced with veterinary medicines under supervision. Never give a second animal a dose calculated for a dog, and never assume that because a substance is safe to bring up in one species it is safe in another.
When vomiting must never be induced
There are substances and situations where inducing vomiting is dangerous, and this list is the reason the professional phone call matters so much. Never induce vomiting if the dog swallowed a caustic or corrosive substance, such as strong acids, alkalis, drain cleaner or oven cleaner: the material burns on the way down and burns again on the way back up, doubling the injury to the throat and food pipe. Never induce vomiting for petroleum products such as petrol, kerosene, lighter fluid or some furniture polishes, because these can easily be inhaled into the lungs during vomiting and cause a serious chemical pneumonia. Never induce vomiting if the dog swallowed a sharp object, such as a needle, a bone fragment with sharp edges, broken glass or a fish hook, because the object can tear the throat or stomach on the way back. And never induce vomiting if the dog is already vomiting, seizing, unconscious, collapsed, or having breathing difficulty: a dog that cannot protect its airway can inhale vomit into the lungs. In any of these situations, skip the hydrogen peroxide entirely and get emergency veterinary help, calling ahead so the clinic is ready when you arrive.
Dogs at higher risk, including flat faced breeds
Some dogs face a higher risk from vomiting itself. Brachycephalic breeds, the flat faced breeds such as Bulldogs, French Bulldogs, Pugs, Boxers, Shih Tzus and Pekingese, have shortened airways and a higher aspiration risk, meaning vomit is more likely to enter the lungs and cause aspiration pneumonia. For these breeds, many veterinarians prefer that any vomiting is induced in the clinic, with the airway watched, rather than at home, so mention the breed prominently on your call. Dogs with a history of aspiration pneumonia, dogs with conditions that affect swallowing or the food pipe, dogs with significant heart or breathing disease, very young puppies, frail elderly dogs, and dogs that have recently had abdominal surgery also deserve individual advice before any home dose is given. This calculator cannot weigh those risks: it only does the arithmetic for a dog that a professional has already cleared for home induction. If the adviser says the dog should be seen instead, that advice overrides the number on this page, and the calculated dose should simply be discarded.
Step by step: giving the dose after you have been advised to
Once a veterinarian or poison control has advised you to induce vomiting, the standard guidance is as follows. First, feed a small meal or a small piece of bread if the dog will eat it: a little food in the stomach makes vomiting more likely to succeed and gives the peroxide something to work with. Second, check the bottle again before you measure anything: it must say 3 percent hydrogen peroxide, and if it does not, stop and call back for advice rather than substituting another product or another strength. Third, measure the calculated dose carefully, using an oral syringe for accuracy rather than guessing with a kitchen spoon, although the result on this page is also shown in teaspoons and tablespoons for reference. Fourth, give the dose by mouth, placing the syringe into the cheek pouch at the side of the mouth and squirting slowly so the dog can swallow rather than inhale the liquid; never force the mouth wide open or squirt straight down the throat. Fifth, walk the dog gently for a few minutes, because gentle movement helps mix the stomach contents and encourages vomiting. Vomiting usually happens within 10 to 15 minutes. Keep the dog somewhere the vomit can be inspected safely, and keep other pets away from it, because the vomited material may still contain the toxin. Note what comes up, since the adviser or veterinarian will want to know whether the swallowed material appears to have been recovered.
The repeat dose rule, and what happens next
If the dog has not vomited after 15 minutes, the standard guidance allows one repeat dose, and only one: a second dose of the same calculated amount, given after 15 minutes, only if there has been no vomiting and only if the veterinarian or poison control advises it. Do not give a third dose. If two doses do not work, more hydrogen peroxide is not the answer; the dog needs veterinary care, where other medicines can be used to induce vomiting under supervision if it is still appropriate. If the dog does vomit, do not assume the problem is over. Call back and report what happened, because some toxins need follow up treatment, monitoring or blood tests even after successful vomiting, and the adviser will tell you whether the dog still needs to be seen. Watch the dog afterwards for ongoing vomiting, drooling, retching without producing anything, lethargy, loss of appetite, stomach pain or breathing changes, and seek veterinary help promptly if any of these appear. Hydrogen peroxide can irritate the stomach lining, and a dog that keeps vomiting after the expected episode has passed needs to be examined rather than given anything further at home.
Worked examples
The table below applies the protocol rate of 1 mL per lb and the 45 mL maximum to a range of common dog weights, so you can sanity check any result this calculator gives you.
| Dog weight | Dose in mL | Teaspoons | Tablespoons | Cap applied? |
|---|---|---|---|---|
| 5 lb | 5 mL | 1 tsp | 0.33 tbsp | No |
| 10 lb | 10 mL | 2 tsp | 0.67 tbsp | No |
| 20 lb | 20 mL | 4 tsp | 1.33 tbsp | No |
| 40 lb | 40 mL | 8 tsp | 2.67 tbsp | No |
| 45 lb | 45 mL | 9 tsp | 3 tbsp | No, reaches the cap exactly |
| 50 lb | 45 mL | 9 tsp | 3 tbsp | Yes, capped |
| 100 lb | 45 mL | 9 tsp | 3 tbsp | Yes, capped |
For weights in kilograms, convert first: divide the weight in kilograms by 0.45359237 to get pounds, then apply the same rate and cap. A 10 kg dog weighs about 22.05 lb, so its dose is about 22.05 mL, roughly 4.41 teaspoons or 1.47 tablespoons, comfortably below the cap. A 25 kg dog weighs about 55.12 lb, so its uncapped figure would be about 55.12 mL, but the cap applies and the dose is 45 mL. If you do not know your dog current weight, use the most recent veterinary weight you have and tell the adviser it is an estimate: do not delay the call to weigh the dog, because the usefulness of inducing vomiting falls as time passes after ingestion.
Sources
ASPCA Animal Poison Control Center guidance on inducing vomiting in dogs (American Society for the Prevention of Cruelty to Animals, Animal Poison Control Center): the protocol reproduced on this page, namely 1 teaspoon (5 mL) of 3 percent hydrogen peroxide per 5 lb of body weight given orally, with a maximum dose of 3 tablespoons (45 mL) regardless of weight, administration after feeding a small meal, a single repeat dose after 15 minutes if vomiting has not occurred and a professional advises it, expected vomiting within 10 to 15 minutes, usefulness mainly within 2 hours of ingestion, and the instruction to contact a veterinarian or the ASPCA Animal Poison Control Center on (888) 426-4435 before inducing vomiting. Merck Veterinary Manual (MSD Veterinary Manual), pet owner and professional guidance on poisoning and on inducing vomiting (emesis) in dogs: the contraindications reproduced on this page, including corrosive and caustic substances, petroleum distillates, sharp objects, and animals that are already vomiting, seizing, unconscious, collapsed or having breathing difficulty, the higher aspiration risk in brachycephalic breeds, and the restriction of this home method to dogs and not cats.