As soon as you realize your dog has consumed a substance that is toxic to canines, call your veterinarian for instructions. Your veterinarian will need to know what your dog ingested and how long ago; and he may instruct you to induce vomiting with hydrogen peroxide to expel the toxin.

To Bring What's Inside Out

Household 3 percent hydrogen peroxide is an irritant to the gastrointestinal tract that, when ingested by a canine, usually results in vomiting. Vomiting expels toxic matter from your dog's stomach before it reaches the colon and is absorbed into his system, potentially causing great harm.

Hydrogen Peroxide Contraindications

Always get your vet's approval before inducing vomiting. In some cases, you should not try to make your dog vomit with hydrogen peroxide. If your dog is already vomiting, this therapy will make his vomiting become violent. When your dog is weak, unconscious or has trouble standing, he can inhale vomit into his lungs and develop aspiration pneumonia.

When your canine companion swallows drain cleaner, bleach or a petroleum product, the chemicals cause damage as they go down and will burn again as they come up, causing greater distress in the stomach, throat and mouth.

Two hours after your dog ingests a toxic substance, it is too late to induce vomiting because the substance is in his small intestine and will not be expelled via vomiting. If you discover the poisoning two hours after ingestion, call your veterinarian for an emergency appointment.

Common Toxic Foods

Many human foods are toxic to dogs. Among them is the avocado, which causes mild to severe stomach upset. Bread dough can expand in the stomach, resulting in labored breathing, distended abdomen, lack of coordination and alcohol intoxication.

Chocolate can cause vomiting, stomachaches, restlessness, muscle tremors, temperature, seizures and death. Any type of alcohol can cause lack of coordination, stupor, disorientation and, in severe cases, coma, seizures and death.

Grapes and raisins can cause kidney failure, and moldy foods can cause muscle tremors and convulsions. Raw onions and garlic damage red blood cells in canines. The no-calorie sweetener in sugar-free products called Xylitol causes a rapid drop in a dog's blood sugar levels, which can cause seizures.

Household Dangers

Outdoor household items that are toxic to dogs include lawn chemicals, such as fertilizers, and cocoa mulch. Antifreeze containing ethylene glycol is a deadly toxin that tastes sweet to dogs and cats. Rat poison is highly toxic to dogs, as are rats that have consumed poison.

Medications and household chemicals need to be out of reach of your dog. If he consumes human medications, flea and tick medicine, human pills, cleaning supplies and other substances, he can suffer the effects of toxicity.

Dosage and Administration