Domestic pet poisoning

Poisoning is a common occurrence in domestic animals like dogs and cats. The most widely observed route of poisoning is via the mouth (orally), but topical poisoning and other routes of intoxication are also possible. No matter the route of poisoning, it’s critical to treat each individual case of poisoning as a matter of urgency, as some poisons could be life-threatening for the pet. In this article, we give an overview of the most commonly encountered poisons in private practice in this part of the world.

What is poisoning?

For our purposes, poisoning is defined as any substance that is ingested or absorbed via the skin, which causes harmful effects in a dog or cat. The substances that are poisonous to pets can range from regular human medications (over the counter, prescription and/or vitamins); human food that is not supposed to be fed to animals such as chocolates or grapes; pesticides; plants; or topical tick and flea treatment that is incorrectly used on the wrong species of pet.

How will I know if my pet has been poisoned?

There is often a rapid onset of the effects of poisons when the toxic dosage has been met – i.e. it will show quickly when your pet has ingested something poisonous. An exception to this is warfarin, which is used in rat poisons. This is a slow-acting poison that, if ingested by your pet, will only show symptoms up to a week or more later. In poisoning cases that are brought to the vet, pet owners usually report a sudden onset of symptoms, presence of the suspected poison in the home environment, rumours of recent malicious activity in the neighbourhood and, most importantly, definite reports of confirmed exposure to the poison; for example, seeing the animal eating the poison.

Common symptoms of poisoning

Signs of poisoning differ between the affected systems. Common symptoms of poisoning include excessive salivation, foaming at the mouth, vomiting, diarrhoea, muscle tremors and/or seizures, as well as abnormal bleeding. At other times the pet might show non-specific signs. However, as mentioned before, a suspicion of poisoning can be made given the sudden onset of the signs fitting poisoning.

Different types of poisoning

  1. Rat poisons

Rat poisons are the most common poisons encountered in practice. Rat poisoning cases can be both as a result of accidental consumption in the home or when visiting neighbours and family, or malicious activity. There are two main types of rat poisoning: a slow-acting poison that affects blood clotting and a fast-acting poison that affects the nervous system as well as exerting effects on the digestive tract. Both types of poisons can prove to be fatal if the specific antidote is not given in time.

RATTEX (warfarin/coumarin) is an example of a poison that affects blood clotting. Usually, if the pet is not seen consuming this type of poison, symptoms will begin to show after a week. The pet can be lethargic and anaemic, as well as have abnormal bleeding. Blood tests are usually performed as part of the diagnosis and treatment monitoring. In general, pets begin to show signs of improvement once the specific antidote is started. Treatment can continue for up to three weeks depending on each case.

Organophosphate and ‘two-step’ poison are examples of poisons that affect the nervous system. These poisons are highly potent and fast-acting. In cases of malicious poisoning, with high dosages of poison being delivered in food, the pet is usually found dead within an hour of ingesting laced food. There is an antidote for this poison, which is beneficial when administered in time. In-hospital care is required for this type of poisoning.

  1. Human medicines

What is very good for the pet owner is often not the best thing for the pets. Human medicines are notorious in animal poisoning cases. They are easily accessible to pets, which means they become common causes of poisoning in animals. Human medicines that can be harmful to pets include painkillers, vitamins and supplements. They can result in kidney injury, gastric ulceration, bone marrow suppression, cardiac function depression, and sometimes, particularly in female unsprayed dogs, female reproductive problems. Given the vastness of the potential effects of human medicines, symptoms are quite diverse and will depend on the specific medication consumed. To further complicate the situation, some effects are not seen immediately and can possibly take a couple of months before being evident. This means the connection between the pet’s symptoms and the consumption of human medicine might be missed.     

  1. Human food

Human food consumed by dogs and cats can also cause pet poisoning. Grapes, chocolate, xylitol, alcohol and macadamia nuts are notorious for poisoning pets. Several other products can also cause poisoning in animals; lists of which are found on the national poison database. Again, depending on the food product consumed, signs of food toxicity can range from diarrhoea, vomiting and nausea, to hyperactivity, tremors, seizures, hypoglycaemia, renal failure and/or death. In general, the vet can induce vomiting if the pet consumed the toxic food less than two hours prior.

  1. Plant poisoning

Different types of toxic plants exist in our home environments. Toxic plants can include flowers or other ornamental shrubs and trees. These plants can cause various detrimental effects in our pets, ranging from localised mouth and tongue reactions, liver damage and liver failure, kidney injury and/or failure, and heart failure. Plant poisoning in dogs and cats can prove to be extremely difficult to diagnose in practice unless the pet owner mentions clues when speaking to the vet. Diagnostic tests can make the case work-up easier and provide a better outcome for the pet. Since there are no antidotes to plant poisonings, pets will be treated for their symptoms and their health managed accordingly.

The elephant leaf garden plant is an example of a plant poison that causes localised irritation and swelling in the mouth and tongue. This type of poisoning is often seen in puppies who will chew at everything they can get to out of curiosity. Treatment is mainly targeted at managing the symptoms and often carries a good prognosis.

Cycad seeds are notorious for causing liver problems in dogs. Usually, pets are presented to the vet showing gastrointestinal signs such as vomiting, increased thirst and profuse salivation. Bloodwork will show evidence of liver disease. In other instances, symptoms are non-specific until a diagnosis is reached following a thorough history-taking and relevant blood test results.

What to do if your pet is poisoned

Simple: take your pet to the vet! If you cannot get to the vet’s office immediately, phone in and ask for advice.

If you have just witnessed your pet consuming poison (within the last two hours or less), quickly get your pet to the vet to induce vomiting – if applicable. In the case of anticoagulant poisons like warfarin, it’s neither wise nor helpful to induce vomiting, as ingestion and digestion would have occurred days before. Depending on the oral poison ingested, it can sometimes be helpful to give your pet activated charcoal to reduce the amount of poison being absorbed. If your pet has just been exposed to a topical poison, the best would be to wash the area on the skin to decontaminate it and reduce the amount of poison being absorbed. Thereafter, rush your pet in for emergency care at the veterinary hospital.  

If your pet is experiencing seizures, it is important to protect them from inadvertently injuring themselves. Keep them in a padded area that is free of sharp protruding objects.

If you know which poison your pet has ingested, take the packaging with you, as this will be useful to the vet. It will save a lot of time unnecessarily searching for diagnostic clues and researching other symptoms and effects to anticipate.

Case management at the veterinarian

A case of poisoning is always addressed as an emergency until an antidote is given and the pet patient is stable. Following the collection of a relevant, brief and concise case history by the vet, any of three main routes might be elected. These include:

  1. Inducing vomiting and stomach washing
  2. Giving the antidote if available, and
  3. Case workup to identify exact systems affected and hopefully the exact cause of poisoning.

Once a diagnosis is reached, treatment is given along with the necessary case monitoring. Patient follow-ups are also very important, and this is where adhering to the vet’s recommendations will be beneficial to the pet.


Prognosis with poisoning cases is case dependent. However, factors that could improve the prognosis of each case include early diagnosis and intervention, the availability (and timely use) of an antidote, and the proper post-treatment follow-up. When dealing with poisons without antidotes, a good response to treatment without permanent vital organ damage usually carries a good prognosis. Prognosis is therefore poor when there is no (or delayed) intervention, as well as damage to vital organs, which could prove detrimental.

As a pet owner, you are encouraged to be vigilant about your pet’s access to potentially poisonous materials. Should they end up in the unfortunate position of being accidentally poisoned, do not rely on home remedies to treat your pet – rather get them to the vet as soon as possible.

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