Chocolate
This is probably the most widely known toxic food for cats and dogs. The symptoms and level of toxicity can range from mild to severe depending on the type of chocolate, how much was ingested, and how big the pet is. The general rule is, the darker the chocolate, the more toxic it is. It is because it contains a higher level of theobromine, which is what causes this toxicity. The biggest concern is with baker’s chocolate and dark chocolate, but even a large enough amount of milk chocolate can put your pet at risk. Symptoms of chocolate toxicity include — vomiting, diarrhea, restlessness, pancreatitis, high blood pressure, hyperthermia, tremors, abnormal heart rhythms, seizures, collapse, and death.
Grapes and Raisins
Grapes and raisins (and even currants) can cause quite a severe toxicity in dogs. If even a small amount is ingested, they could go into acute kidney failure. Other common symptoms include vomiting, diarrhea, anorexia, lethargy, and abnormal drinking or urination.
Onions and Garlic
Members of the Allium family (onions, garlic, chives, leeks, etc.) are toxic to dogs and cats. Onion/garlic poisoning can damage the animal’s red blood cells, making them more likely to rupture. It can also cause gastrointestinal issues, such as nausea, vomiting, diarrhea, and drooling, as well as other symptoms like lethargy, pale gums, increased heart rate and respiratory rate, weakness, and collapse.
Fatty Foods
While hamburgers, bacon, french fries, and other greasy foods may be delicious, they are not good for our bodies and the same goes for our pets. Slipping your dog bites of these high-fat foods can lead to an upset stomach – vomiting, diarrhea, gas, etc. A large enough fatty meal can also cause an unpleasant case of pancreatitis.
Avocado
Avocados contain a toxin called “persin,” but this toxin is only poisonous to species like birds and cattle. Avocados do, however, pose the risk of gastrointestinal obstruction when ingested by a dog or cat. The seed (or the entire avocado if swallowed whole) can get stuck in the GI tract. Signs of this would include vomiting, diarrhea, lack of defecation, and anorexia.
Alcohol
This should be an obvious one, but alcohol toxicity in pets is more common than you think. It isn’t necessarily because of people flat out allowing their pets to drink alcohol (although those people do exist). Alcohol is present in more things than many of us realize. For example, unbaked bread dough is full of yeast which can ferment in the stomach (much like it does to make beer) and lead to alcohol poisoning. Ingestion of alcohol will cause symptoms such as vomiting, distended bloated stomach, low blood pressure, low blood sugar, hypothermia, weakness, collapse, seizures, difficulty breathing, and in severe cases, death.
Cooked Bones
While raw bones can sometimes make a good treat for your dog (however should always be given with caution), cooked bones are extremely dangerous. They are much more brittle and can splinter into sharp shards very easily. If these pieces of bone are swallowed, your dog or cat could end up cutting their tongue or mouth, or face a penetrating foreign body in the esophagus, stomach, or intestinal tract. Large pieces of bone that are broken off and swallowed can also cause a complete gastrointestinal blockage. You may also see constipation, severe abdominal discomfort, or bleeding from the rectum if a sharp piece scrapes and cuts the intestinal wall.
Cherries
Cherries contain cyanogenic glycosides and are considered toxic to cats and dogs. This toxin affects the cells in the body to properly take in oxygen. Common signs of cherry toxicity include dilated pupils, difficulty breathing, low oxygen levels, bright red gums, shock, and in extreme cases death.
Mushrooms
While the majority of mushrooms are not toxic, there are some that can cause severe and sometimes fatal toxicities in cats and dogs. For this reason, it is best to avoid feeding all mushrooms to your pet. Some common symptoms associated with toxic mushroom ingestion include nausea, vomiting, diarrhea, drooling, a painful abdomen, depression, walking drunk, tremors and seizures.
Macadamia Nuts
It is currently not known what causes macadamia nuts to be toxic, but they should indeed be avoided in dogs. Clinical signs of macadamia nut toxicity include severe lethargy, fever, vomiting, tremors, joint stiffness, and the inability to walk.