Suspected poisoning in a dog: the first hour, and the myths that waste it

Quick answer

The first hour matters because it is the window in which the poison can still be removed. Once a substance has left the stomach and entered the circulation, treatment shifts from removing it to supporting the organs it is damaging, and the outcomes are worse.

What that hour should not be spent on is making the dog sick at home. Inducing vomiting without instruction is the single most damaging piece of folk advice in this area, and for several common poisons it turns a manageable case into a critical one.

The useful work in the first hour is information gathering and one phone call, not treatment.

• Phone a vet or an animal poison service immediately. Do not wait for signs to appear.
• Do not induce vomiting unless a vet tells you to and tells you how.
• Keep the packaging, the label, and any remains. The exact product decides the treatment.
• Know the dog's current weight. Toxicity is a matter of dose per kilogram, and a guess can change the advice.
• For many poisons the signs appear long after the window for effective treatment has closed.

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Never induce vomiting at home unless a vet has told you to.

Corrosive substances, including drain cleaner, oven cleaner, dishwasher tablets and detergent capsules, burn the oesophagus a second time on the way back up and can perforate it.

Petroleum based products, including petrol, white spirit, lamp oil, paraffin and some wood treatments, are thin and slippery. If a dog vomits them, they are readily inhaled into the lungs and cause a severe chemical pneumonia that is frequently worse than the poisoning itself.

A dog that is already drowsy, unsteady, seizuring or unconscious will inhale its own vomit. So will many brachycephalic dogs, and dogs with laryngeal paralysis or megaoesophagus.

Salt water as an emetic is dangerous in its own right and has killed dogs through sodium poisoning. Mustard, milk and cooking oil do not work. Hydrogen peroxide causes stomach ulceration and is only used under direct veterinary instruction where it is used at all.
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Decide in 60 seconds

Why the first hour is different

A swallowed substance sits in the stomach for a period before it moves into the small intestine, where almost all absorption happens. While it is still in the stomach it can be removed, and what remains can often be bound by activated charcoal before it is absorbed.

Once absorption is under way, none of that is available. Treatment becomes fluid therapy, medications to protect organs, monitoring, and in a few cases a specific antidote.

This is why the standard advice is to phone before there are any signs. For a great many poisons the dog looks entirely normal during exactly the period when intervention works, and looks unwell only once the damage has begun.

Two examples make the point. Anticoagulant rodenticide causes no visible change for several days, and the first sign may be bleeding into a body cavity. Grapes and raisins produce vomiting early and kidney failure later, and the kidney injury is not reversible once established.

The information that changes the treatment

What. The exact product, with the packaging if possible. Brand names matter, because different rodenticides in similar boxes contain completely different active ingredients with completely different treatments and antidotes. Photograph the label including the small print listing the active ingredient.

How much. Count what is missing rather than estimating. How many tablets were in the packet, how much was left in the bag, how big the block was.

When. The time of ingestion, or if unknown, the last time you know the dog was fine. This determines whether decontamination is still worth attempting.

The dog's weight. Current weight, not the weight from last year. Everything is calculated per kilogram.

The dog itself. Age, breed, existing conditions, current medications, pregnancy. A dog on non steroidal anti inflammatories, or with existing kidney disease, has a much narrower margin.

Take the packaging with you to the practice. Do not clean up the scene until you have recorded what was there.

The common poisonings, and what each one does

Chocolate. The active compounds are theobromine and caffeine, which dogs clear slowly. Dark and cooking chocolate contain much more than milk chocolate, and cocoa powder and cocoa mulch more still. Signs include restlessness, a fast heart rate, vomiting, tremors and seizures, and they typically begin hours after eating.

Xylitol, also labelled birch sugar or E967. Found in sugar free gum, mints, some peanut butters, protein bars, baked goods, some medicines and some toothpastes. In dogs it triggers a large insulin release, causing low blood sugar that can appear within under an hour, and at higher exposures it causes liver failure over the following days. This is one of the fastest acting and most underestimated household poisons.

Grapes, raisins, sultanas and currants. Cause acute kidney injury in some dogs. The dose that causes it is unpredictable, individual dogs vary enormously, and dried forms are more concentrated. Any ingestion is treated seriously. Mince pies, fruit cake, scones and cereal bars are common sources.

Onions, garlic, leeks, chives and shallots. Cause oxidative damage to red blood cells, producing anaemia that appears over several days rather than immediately. Cooked and powdered forms count, so gravy, stock, stuffing and takeaway leftovers all matter.

Ethylene glycol antifreeze. Sweet tasting and rapidly absorbed. It causes drunkenness first, then apparent improvement, then fatal kidney failure. The antidote is effective only if given early, so this is a same hour emergency and not a same day one. Screenwash and some brake fluids may also contain it.

Rodenticides. Not one poison but several. Anticoagulant types stop blood clotting and cause bleeding after a delay of days, and have a specific antidote given for weeks. Bromethalin causes brain swelling and neurological signs. Cholecalciferol raises blood calcium and damages the kidneys. Alphachloralose causes hypothermia and sedation. There is no way to guess which one from the appearance of the bait, which is why the packaging is essential.

Metaldehyde slug pellets. Cause tremors, seizures and dangerous overheating, and they act quickly. Blue and green pellets are also attractive to dogs.

Human medicines. Ibuprofen and naproxen cause stomach ulceration and kidney damage at doses far below human ones. Paracetamol damages the liver. Antidepressants can cause agitation, tremor and high temperature. Stimulant medication for attention disorders is dangerous in small amounts. Vitamin D analogue creams for psoriasis are a classic and severe poisoning from a licked skin cream or a discarded tube. Blood pressure and heart medications drop blood pressure dangerously.

Nicotine, including vape liquid and pouches. Rapidly absorbed and acts within minutes.

Cannabis and edibles. Cause wobbliness, dilated pupils, dribbling urine, an exaggerated startle response and depression. Edibles are worse than the plant material because they usually also contain chocolate or xylitol. Being honest with the vet about what was in the house changes the treatment and is not a legal matter for them.

Blue green algae. In warm standing or slow moving water. Can cause liver failure or neurological collapse very quickly after swimming or drinking.

Raw bread dough. The yeast continues to ferment in the warm stomach, producing alcohol and expanding. The dog gets both alcohol poisoning and a physically distending stomach, which is a surgical emergency.

Macadamia nuts. Cause weakness, tremors, vomiting and an unsteady back end.

Detergent capsules and batteries. Corrosive burns to the mouth and oesophagus. Never induce vomiting. Batteries also cause pressure and current injury if lodged.

Skin, eye and inhaled exposure

The rules are different when the substance has not been swallowed.

For skin contamination, stop the dog licking it first, since grooming converts a skin exposure into an ingestion. Then wash with lukewarm water and a mild washing up liquid, wearing gloves, and rinse thoroughly. Never use white spirit, petrol, turpentine or nail polish remover to remove tar, oil or paint, because those are absorbed and cause chemical burns.

For eye exposure, flush gently with lukewarm water or sterile saline for a prolonged period and phone the vet. Do not use anything else in the eye.

For inhaled exposure, move the dog to fresh air immediately and ventilate the space. Take care of yourself first if the fumes are still present.

The myths worth naming

Gum colour and refill time are useful observations to report, but they never replace phoning about the substance itself.

Make the dog sick. Covered above. It is dangerous for several common poisons and unnecessary when a vet can do it safely and effectively with the right drug.

Salt, mustard or washing up liquid to induce vomiting. Salt causes its own life threatening poisoning. The others do not reliably work.

Give milk or bread to line the stomach. Neither neutralises anything. For some fat soluble toxins, fatty food increases absorption.

Wait and see whether the dog gets ill. The most costly myth of all, because the treatable window closes while the dog still looks well.

Give activated charcoal from a health food shop. Charcoal is genuinely useful for some toxins, useless for others such as ethylene glycol and xylitol, contraindicated when the airway is not protected, and requires the right dose and sometimes repeated doses. It also causes aspiration if given to a drowsy dog. It is a treatment, not a first aid item.

It was only a small amount. Toxicity is per kilogram. The same square of chocolate is nothing to a large dog and significant to a terrier.

Dogs instinctively avoid things that are bad for them. They do not. Many of the worst poisons taste sweet.

Bringing the vomit is unnecessary. Bringing a sample of vomit, or a photograph of it, is genuinely useful and helps identify what was eaten.

Prevention that actually holds

Store rodenticides, slug pellets, antifreeze and garden chemicals where a determined dog cannot reach them, which usually means a locked or high cupboard rather than a shelf in a shed.

Keep human medicines out of bags, bedside tables and coat pockets. Visitors' handbags left on the floor are one of the commonest sources of medicine and chewing gum poisonings.

Assume anything labelled sugar free contains xylitol until you have read the ingredients.

Keep bins closed and secured, including compost bins, which produce moulds that cause tremors and seizures.

Know what is in your garden. Check plants and bulbs, and be aware that spring bulbs dug up and chewed are a seasonal pattern.

Do not let dogs swim in or drink from water with a green or blue green scum on it.

Do not leave chocolate, dried fruit or baked goods where a dog can reach them, particularly during holidays, which is when most cases occur.

Save the number of your vet, the out of hours service and an animal poison line in your phone now, before you need them.

When to get help

Contact a vet or an animal poison service immediately for any suspected ingestion, before signs appear, and regardless of how small the amount seems.

Go straight to a practice, phoning on the way, for a dog that is wobbly, drowsy, twitching, seizuring, collapsed, breathing with difficulty, or that has swallowed a corrosive or petroleum product.

A good outcome usually comes from a fast phone call and accurate information, not from anything done to the dog at home.

Take the packaging, a photograph of the label and ingredient panel, any remaining product, a sample or photograph of any vomit, and the dog's current weight. Say clearly what you know and what you are guessing at, because a vet plans around uncertainty differently from certainty.