Category Archives: Toxicity

Grape Toxicity, Canine

Grape and Raisin Toxicity
By Dr. Karen Burgess

Picking ripe grapes from the vine is fun for all. But at the same time grapes and raisins can be very dangerous for dogs and possibly cats. The exact mechanism of this toxicity is not understood and a variety of grapes (seedless or not, green or red) have been implicated along with raisins. Even more frustrating is that there is not a specific toxic dose nor are all animals affected equally.

How many grapes or raisins are a problem?
Grape toxicity is not dose dependent, meaning that the amount of exposure does not correspond well to signs of disease or severity. Previous safe exposure to grapes also does not affect a pet’s susceptibility to toxicity. The toxicity of grape juice and grape jelly are not known so should also be avoided. Grapeseed extract is thought to be safe.

Signs of grape toxicity
The first and only symptoms may be those of gastrointestinal upset (vomiting, diarrhea, inappetance). These symptoms may be present for weeks after ingestion in some cases. In severe cases, potentially fatal kidney failure can occur 12 to 72 hours after ingestion.

What to do if your pet ingests grapes/raisins
Contact your veterinarian, animal emergency hospital, or animal poison control immediately. If ingestion has just occurred, often medication can be given to induce vomiting. Hospitalization for further decontamination, intravenous fluid therapy, and monitoring of kidney values/lab work may also be recommended. If after 3 days there is no sign of kidney disease, the prognosis is typically favorable. In cases of kidney failure, the prognosis is often grave. It is best to contact poison control to determine the risk associated with any given exposure.

OTC Drug Toxicity

Over The Counter Drug Toxicity
By Dr. Karen Burgess

There are numerous over the counter pain relievers readily available to people.  Often these medications may seem like an affordable and simple thing to try for your dog or cat, but many of these products can be very dangerous even at seemingly safe doses.

Aspirin falls into a category of drugs called non-steroidal antiinflammatories or NSAID for short.   There are many NSAIDS available for pets and humans and as a class they are effective pain relievers and blockers of inflammation.

Depending on the chemical makeup of a particular NSAID there can be varying degrees of negative side effects.  After ingestion of aspirin, salicylate is the potentially toxic metabolite produced in the body.  The most common side effects seen with Aspirin include stomach wall bleeding (ulcers), slower clotting times (tendency to bleed), and kidney damage.  While the pain relieving benefits tend to be brief (8 to 12 hours), toxic effects tend to last much longer (7-10 days).  In one study it was shown that all dogs given aspirin at an appropriate dose had visible gastric bleeding.  While many think that enteric coated or buffered aspirin are a safer option, the coating allows variable absorption and in humans are associated with increased risk of gastrointestinal bleeding.  Aspirin is rarely recommended for pain relief in human medicine anymore as there are safer options available.  The primary way aspirin is now used for people is at low doses (think baby aspirin for an adult) to “thin blood” or help prevent clot formation.

Unfortunately for the unknowing pet owner, aspirin is readily available in the pet care aisle and even labeled for pet use.  Many assume because marketed in this way that this is a safe option when in fact it can be a very dangerous choice.  Current acceptable dosing for aspirin is also the dose which can cause stomach ulcers.  Additionally, after even one dose of aspirin no other NSAIDs or steroids should be used for 7 days.  This means that much needed effective and safe pain relief may not be an option for your veterinarian to prescribe after aspirin use.

For cats aspirin is particularly dangerous.  Ingestion of even one aspirin would likely be fatal.  The metabolism of aspirin is much slower in cats making a daily dose of baby aspirin extremely dangerous.

Signs of toxicity from aspirin including vomiting (with or without blood), diarrhea, loss of appetite, bloody or black stool, excessive bruising, bone marrow suppression, weakness/depression, or death.

Baby aspirin contains 81 mg aspirin, regular strength 325 mg, and extra strength 500 mg.  What many may not realize is that Pepto-Bismol products may contain 262 mg salicylate per TBSP or 300 mg salicylate per tablet.  Check all labels carefully before giving a medication to your pet as aspirin is a common add on ingredient in over the counter products.

Ibuprofen is an NSAID that decreases inflammation, reduces fever, and provides pain relief.  Toxicity concerns are similar to Aspirin (gastric ulceration, clotting issues).  Similar to aspirin, there is a dose recommendation for dogs, but this is typically discouraged due to potential negative side effects.  Cats are less tolerant of ibuprofen than dogs.

Acetaminophen provides both pain and fever relief but does not affect inflammation or clotting like NSAIDs.  While the safe dose range is narrow, in many dogs acetaminophen products may be a safer option to assist with pain.  Cats lack the ability to break down acetaminophen in the liver and even one dose of acetaminophen may be fatal (10 mg/kg).  Toxic dose in dogs are typically seen at doses exceeding 100 mg/kg.

Symptoms of toxicity may be more likely to develop in smaller dogs or those with underlying liver disease.  Lethargy, swollen face, blue gums, shortness of breath, and yellow tinged skin are all possible signs.  Hospitalization and intensive treatment may be necessary with more serious exposure.


Essential Oil/Potpourri Toxicity

Essential Oils/Liquid Potpourri Toxicity
By Dr. Karen Burgess

Liquid potpourri and essential oils (liquid concentrate from plants) are often found in the household.  While appealing to the human nose, these products can be toxic after to cats and dogs after ingestion or skin exposure.

What makes essential oil/liquid potpourri toxic?
Essential oils are made from plant concentrate.  The two toxic components of liquid potpourri are cationic detergents (found in laundry detergents, sanitizing products) and essential oils. They are commonly used in aromatherapy, medicinally, and in home goods to enhance aroma.  Some oils of particular concern include peppermint, lemon, lavender, melaleuca, tea tree, cinnamon bark, wintergreen, thyme, birch, and any phenol containing product.  Dry potpourri tends to be less of an issue as it contains only essential oils and no cationic detergents.

What problems do potpourri and essential oils cause?
Liquid potpourri and essential oils are rapidly absorbed both through the skin and orally.  After exposure they are then processed by the liver.  This can can cause particular difficulty for cats that lack the ability to break down these chemicals, the very young, and those with underlying liver disease.  The liquid components are also capable of irritating/burning the skin and mouth making only a lick or two a danger.  Often cats can be exposed when oils come in contact with their fur and they then groom themselves.

Signs of potpourri/essential oil toxicity
Signs of exposure may being with drooling, a painful mouth/pawing at mouth, and oral redness with first exposure.  More serious signs include weakness, walking as if drunk, tremors, and difficulty breathing.

What to do if your pet is exposed to potpourri/essential oils
Contact your veterinarian, animal emergency hospital, or animal poison control immediately.  Do not induce vomiting as this may worsen symptoms.  With eye exposure copious rinsing is recommended immediately.  If the skin has been exposed, using mild dishwashing soap to remove it is appropriate.  With ingestion or oral exposure, drinking milk/dairy product may help neutralize the detergent effect of liquid potpourri.  Hospitalization, intravenous fluids, and liver monitoring may be indicated based on exposure and clinical signs.  Prevention of exposure is key.  Consult your veterinarian before using any supplements and never put pure essential oils on a pet.  Be aware of open liquid potpourri pots being a potentially toxic curiosity for dogs and cats.

Chocolate Toxicity

Chocolate Toxicity
By Dr. Karen Burgess

Chocolate while tasty to humans can be toxic to dogs and cats.  Found commonly in candy, baking products, and cocoa bean mulch, it is often not difficult for household pets to be exposed.

What makes chocolate toxic?
Chocolate contains the toxic methylxanthines theobromine and caffeine.  Both of these agents medically dilate blood vessels, relax smooth muscles, stimulate the heart, and act as diuretics.  Theobromine tends to be the more toxic.

What products contain chocolate?
Cocoa powder, semi sweet, dark, white, and milk chocolate all contain varying amounts of theobromine/caffeine.  More recently the use of cocoa beans as mulch has also caused problems for dogs.

What problems does chocolate cause in dogs?
Methylxanthines stimulate the nervous system, cause fluid changes in the body, and affect contractility of heart and skeletal muscles.

How much chocolate does it take to cause problems?
As little as 9 mg of theobromine per pound of body weight can result in milder signs of toxicity.  Toxicity is severe above 25 mg of theobromine per pound and may be life threatening at doses of 130 mg of theobromine per pound of body weight.  As a reference, baking and some dark chocolates contain 130 to 450 mg of theobromine per ounce of product.  At the other end of the spectrum, milk chocolate typically contains 50 mg of theobromine per ounce and mild chocolate a mere 0.25 mg of theobromine per ounce.  This means that even a half pound of milk chocolate can cause major health problems for a dog.  Two small squares of Bakers chocolate would be a major concern in a dog as big as 60#.

Signs of chocolate toxicity
Common signs include vomiting, diarrhea, increased thirst/urination, agitation/restlessness, elevated heart rate, and seizures.  Sudden death can occur in particular in pets with underlying heart disease.

What to do if your pet ingests chocolate
Contact your veterinarian, animal emergency hospital, or animal poison control immediately.  Be prepared to provide specific information regarding ingestion; product name, amount/weight, ingredients including type of chocolate.  Unfortunately it may take several hours for symptoms to develop and they may then last for several days.  Theobromine is re-absorbed through the bladder wall allowing for re-introduction of the toxin to the body.  Do not induce vomiting unless under the direction of a veterinarian as aspiration may be a concern.  Decontamination, hospitalization, intravenous fluid therapy, indwelling urinary catheterization, and heart monitoring may all be indicated.


Xylitol (sugar-free gum) Toxicity

Xylitol Toxicity
By Dr. Karen Burgess


Xylitol is a little considered sweetener found in several brands of chewing gum that is highly toxic to dogs.  Over the last few years its popularity has increased thus causing increased risk of exposure.

What is xylitol?
Xylitol, a naturally occurring sugar, is found in corn, plums, berries, lettuce, oats, mushrooms, and various trees.  Once manufactured, the white powder produced is very similar to sugar in its appearance and taste.  Containing a third of the calories of traditional sugar, xylitol is preferential for diabetic humans.  Once processed, xylitol is a white powder that looks and tastes similar to sugar and has been proven to actually decrease cavity formation in humans.  All of these positives for humans has increased the popularity of xylitol in the marketplace over the last several years.

What products contain xylitol?
The most common and easily accessible xylitol containing products include Ice Breakers, Orbit, Stride and Trident chewing gums.  Other sources include diabetic candies, baking additives, Jell-O sugar free pudding, children’s vitamins, nasal sprays, and over the counter medications such as children’s Allegra.

What problems does xylitol cause in dogs?
Severe and sudden drops in blood sugar, liver failure, seizures, and death can all occur from xylitol ingestion in dogs.  In humans xylitol does not cause release of insulin.  However in dogs, it is a potent stimulator of insulin release from the pancreas which leads to a rapid and severe drop in blood sugar levels.  This low blood sugar level (hypoglycemia) can quickly become a life threatening situation.  High doses of ingestion can also lead to liver failure for yet unknown reasons, often 2-3 days after ingestion.  Pets that experience this condition do not always show signs of low blood sugar initially making follow up monitoring very important.

How much xylitol does it take to cause problems?
The toxicity concerns begin at 50 mg/pound of dog.  While different brands contain diiferent amounts of xylitol, the typical range is 300 to 1500 mg/piece of gum.  This means a 20lb dog can experience toxicity after ingesting just one  piece of gum containing 1000 mg.   As one can imagine, the scenario is even worse for smaller dogs.  Liver failure becomes a concern at a dose of approximately 2000 mg/pound.

Signs of xylitol toxicity
Common signs of hypoglycemia, which may develop in as few as 15 minutes, include vomiting, walking as if drunk/weakness, depression, tremors/seizures, and coma.

What to do if your pet ingests xylitol
Contact your veterinarian, animal emergency hospital, or animal poison control immediately.  Do not induce vomiting unless under the direction of a veterinarian as this may worsen developing hypoglycemia.  If clinical signs are apparent hospitalization, laboratory work, and treatment for low blood sugar will likely be indicated for a minimum of 24 hours.  Follow up laboratory work will help determine whether damage has also occurred to the liver.  Prognosis is good if caught early before symptoms develop or with only mild signs.  Pets that develop coma or liver failure carry a poor prognosis for survival.

  • Ice Breakers: 1-1.5g/piece
  • Orbit: 9.2mg/piece or none at all
  • Orbit Strawberry mint: 317mg/piece
  • Stride: 185mg/piece
  • Trident (regular): 0.22g/piece
  • Trident (Xtracare): 0.28g/piece

Plant Toxicity

Common Plant Toxicity Concerns
By Dr. Karen Burgess

the belief that the poinsettia is toxic is somewhat of an urban legend as this common Christmas plant is actually fairly benign.  The milky sap produced can cause oral irritation and mild stomach upset but these symptoms are typically self limiting and do not require veterinary intervention.

Toxic to pets and often found in holiday arrangements, holly contains methylxanthines similar to chocolate.  The leaves are somewhat prickly which may discourage ingestion.  Holly can be both irritating to the mouth and cause severe vomiting and diarrhea. Typically pets do not ingest enough of the plant to cause serious symptoms.  Both Holly leaves and berries are toxic.

Unlike the poinsettia plant, mistletoe can cause significant symptoms in pets including GI upset, neurologic signs (lethargy, seizures, coma), and difficulty breathing.  The amount of mistletoe that would cause toxic signs is not well understood.  Fortunately, most pets do not ingest enough to cause serious consequences.

Sudden and severe kidney failure in cats is associated with ingestion of very small amounts (ex. couple of bites, exposure to pollen) of this extremely common plant.  Vomiting is the most common initial symptom.  This will often resolve initially.  Within 1 to 3 days complete and irreversible kidney failure can develop.  If treatment is started within 18 hours of ingestion (including hospitalization and aggressive fluid therapy for a minimum of 48 hours), prognosis may improve.  Lilies are not toxic to dogs.

Tulip and Hyacinth bulb toxic components are concentrated in the bulb. Ingestion of bulbs can cause GI signs including anorexia, vomiting, and diarrhea.  In more severe cases nervous system signs can develop.

Tomato plants (leaves, fruits, and roots) contain a chemical called solanine which acts to naturally protect plants from pests and fungus.  Found in highest concentration in young or green fruit, solanine can cause a range of signs from gastrointestinal upset to more serious neurological signs.  Fortunately absorption is poor orally and therefore intervention is rarely necessary.  Potatoes also contain solanine and can cause similar signs.

Although containing potentially toxic pyrethrins, mums are considered minimally toxic in pets causing primarily gastrointestinal upset.

Pyrethrin Toxicity

Pyrethrins, Permethrins, and Pyrethroids
By Dr. Karen Burgess

Pyrethrins, permethrins, and pyrethroids are all are natural products used to repel and kill insects.  While organic in origin, pyrethrins are extremely toxic for cats and fish and lesser so in dogs.

What are pyrethrins?
Pyrethrins are a natural insect repellent and insecticide that tends to break down readily and are derived from the flower of the mum (Chrysanthemum cinerariaefolium).  Over the years pyrethrins have started replacing the more toxic organophosphate products.   Pyrethroids (including permethrin) are synthetic versions of pyrethrins and tend to break down slower in the environment.  The primary action of pyrethrins is on an insect’s nerve center causing almost instantaneous paralysis.  Some insects have developed resistance to natural pyrethrins over the years, thus leading to development of the longer acting pyrethroids.  In some cases additional potentially toxic components (ex. organophosphates) are added to pyrethroids to enhance their efficacy.

What products contain pyrethrins?
Pyrethrins are commonly found in yard treatments, foggers, and dog or cat flea products (shampoos, powders, topical spot ons).

How much pyrethrin exposure is a problem?
For cats or fish, any pyrethrin exposure is a concern.  Remember to keep your dog out of water that may have fish until any topical flea product has completely dried (or 48 hours to be safe).  Products containing pyrethrins have varying percentages of concentration.  If exposure or toxicity is a concern, please contact your veterinarian or animal poison control immediately.

What problems and symptoms do pyrethrins cause?
Symptoms of toxic exposure start shortly after exposure and include drooling/excessive salivation, vomiting, agitation, and gagging.  Some dogs have a skin type of reaction to pyrethrins that may look like excessive itchiness (feeling of pins and needles), restlessness, or whimpering/crying.  Severe exposure may progress to seizures, severe depression/coma, and death.  Cats experience similar but often more severe signs and should be considered an immediate and potentially life threatening emergency.  Often the first sign cat owners notice is trembling or excessive shaking.

What to do if you feel your pet has been exposed to toxic amounts of pyrethrins
Contact your veterinarian, animal emergency hospital, or animal poison control immediately.  If your cat has been exposed to pyrethrins toxicity can be life threatening.  Hospitalization, decontamination (removing product from skin or stomach), muscle relaxants, and supportive care are indicated until no further symptoms are noted.  Prevent exposure by reading product labels carefully (make sure safe to use on cats, correct formula for your pet’s weight) and not allowing cats access to dogs treated with pyrethrins for at least 24 hours.

Ice Melt Toxicity, Canine

Ice Melt Toxicity
By Dr. Karen Burgess


What is ice melt?
There are a variety of products that are available to assist with ice accumulation. These liquid (more commonly used commercially) or pelleted consumer products often contain sodium chloride, potassium chloride, magnesium chloride, and calcium salts.

What should I do if my pet has been exposed to ice melt?
With topical exposure the main risk is from local irritation. Bathing your pet to remove the substance from their skin is recommended.  If ice melt is ingested, Animal Poison Control or your local veterinarian/emergency hospital should be contacted.  Ice melt ingestion can cause life threatening alterations in a pet’s electrolytes requiring hospitalization, fluid therapy, and monitoring. Induction of emesis (vomiting) is not recommended unless directed by your veterinarian; in some cases this may worsen the situation if a pet has been exposed to ice melt.