To induce vomiting in a dog, you give 3% hydrogen peroxide by mouth at a dose of one teaspoon per five pounds of body weight, up to a maximum of three tablespoons for dogs over 45 pounds. This is an emergency measure for when your dog has swallowed something potentially toxic and you cannot get to a veterinarian immediately. Before administering it, you need to confirm that vomiting is actually safe for the specific substance your dog ingested, because in some cases bringing it back up causes more damage.
The Correct Dose
Use only regular 3% hydrogen peroxide, the kind sold in brown bottles at drugstores. Higher concentrations are dangerous. The standard dose is one teaspoon (5 ml) per five pounds of body weight. A 20-pound dog gets four teaspoons. A 50-pound dog gets the maximum of three tablespoons (45 ml), and you do not exceed that amount regardless of how much larger your dog is. A 90-pound dog still gets three tablespoons.
If your dog does not vomit within 5 to 10 minutes, you can repeat the same dose one time. Do not give a third dose. If two rounds don’t work, you need a veterinarian.
How to Administer It
The easiest method is using a needleless oral syringe or a turkey baster. Draw up the correct amount, then gently pull your dog’s lip out at the corner of the mouth to create a small pocket. Squirt the liquid slowly into that pocket, giving your dog time to swallow rather than gasp. Aim for the back of the tongue if your dog is cooperative, but don’t force the syringe down the throat.
Feeding your dog a small amount of bread or a few treats beforehand can help. Having something in the stomach gives the hydrogen peroxide more to work with and often makes vomiting more productive. After dosing, walk your dog around gently. The movement helps trigger the vomiting reflex. Most dogs vomit within 10 to 15 minutes.
Do this outside or on an easy-to-clean surface. Once your dog vomits, check what comes up to confirm the toxic item was expelled. Keep your dog calm afterward.
When You Should Not Induce Vomiting
Hydrogen peroxide is not safe to use in every poisoning situation. Some substances cause far more damage on the way back up than they did going down. Never induce vomiting if your dog swallowed:
- Caustic or corrosive substances like bleach, drain cleaner, oven cleaner, or strong acids and bases. These burn the esophagus and mouth a second time during vomiting.
- Petroleum products like gasoline, kerosene, or motor oil. These are easily inhaled into the lungs during vomiting and cause chemical pneumonia.
- Sharp objects like bone fragments, needles, or pieces of glass. These can tear tissue on the way up.
You should also skip hydrogen peroxide if your dog is already showing signs of serious toxicity: seizures, extreme lethargy, loss of consciousness, or difficulty standing. A dog that is seizing or too sedated to swallow properly can inhale the vomit into the lungs, causing aspiration pneumonia. If your dog is showing any of these symptoms, go directly to an emergency vet.
Risks and Side Effects
Hydrogen peroxide works by irritating the stomach lining, which is what triggers vomiting. That same irritation can cause real damage. Known complications include inflammation of the stomach and upper intestine, and in some cases, actual ulcer-like lesions in the digestive tract. There is also a small risk of aspiration pneumonia if your dog inhales vomit into the lungs. In rare cases, the gas produced by hydrogen peroxide can cause the stomach to bloat, a condition called gastric dilatation that can become life-threatening, particularly in large, deep-chested breeds.
Because of the stomach irritation, veterinary toxicologists recommend that dogs receive stomach-protecting medication after hydrogen peroxide use. This is something your vet can provide at a follow-up visit. Even if your dog seems fine after vomiting, a vet check is worthwhile to assess whether the toxin was fully expelled and whether the stomach needs treatment.
Flat-Faced Breeds
There’s a common concern that brachycephalic breeds like Pugs, Bulldogs, and Boston Terriers face higher aspiration risk during vomiting because of their shortened airways. A study published in the Journal of the American Veterinary Medical Association found no increased rate of complications when vomiting was induced in brachycephalic dogs compared to other breeds. Facial conformation alone is not a reason to withhold vomiting induction. That said, flat-faced dogs do have narrower airways in general, so extra caution and a follow-up vet visit remain good practice.
What to Do Before and After
Before giving hydrogen peroxide, try to identify exactly what your dog ate, how much, and how long ago. Call the ASPCA Animal Poison Control Center (888-426-4435) or the Pet Poison Helpline (855-764-7661) if you can. They can tell you whether vomiting is appropriate for the specific substance and guide you through the process. Both services charge a consultation fee, but they provide case-specific advice that could prevent you from making the situation worse.
Timing matters. Hydrogen peroxide is most effective within the first 30 minutes to two hours after ingestion. After that, the substance has likely moved past the stomach and vomiting won’t recover it. If more than two hours have passed, head to the vet instead.
After your dog vomits, withhold food for a few hours to let the stomach settle. Offer small amounts of water. Watch for continued vomiting, bloody stool, loss of appetite, or lethargy over the next 24 hours, as these can signal stomach damage or incomplete removal of the toxin.