Avocados: Every part of an avocado contains a toxin called persin. If consumed, it can cause breathing difficulties, upset stomach, and fluid buildup in the chest. The slippery pit is the most dangerous because it can be accidentally swallowed and obstruct the gastrointestinal tract.

Chocolate: Chocolate is probably the most common food that is bad for dogs. It contains caffeine and theobromine which makes it fall under the methylxanthines category. White chocolates contain fewer methylxanthines making it less toxic. This is also where the phrase “the darker the chocolate, the more dangerous,” comes from. Chocolate can cause vomiting, dehydration, abdominal pains, severe agitation, muscle tremors, irregular heart rhythm, elevated body temperature, seizures and even death.

Yeast Dough: Yeast dough from making bread can ferment in a dog’s stomach, which becomes toxic. Not only will alcohol be produced in the stomach, it can expand the stomach creating large amounts of gas. This can cause severe pain and may also rupture the stomach or intestinal tract.

Milk: Yes, milk. Puppies drink milk from their mothers after birth, but this doesn’t mean it’s okay for dogs to consume later in life. Dogs don’t have the proper enzymes to break down the sugar in milk. If consumed it could lead to vomiting, diarrhea, and other gastrointestinal problems.

Cheese: In addition to containing sugars like milk, cheese also has fatty components which dogs can’t break down. If a dog eats too much cheese some symptoms like gas, diarrhea and vomiting can occur.

Grapes: The chemicals and compounds that are toxic to dogs are still unknown. If a dog eats grapes or raisins it can cause rapid kidney failure. They can also develop vomiting, diarrhea, dehydration, and lack of appetite. In severe cases, death from kidney failure may occur within three to four days.

Coffee: Coffee and the caffeine it contains stimulates the nervous system in dogs and can cause vomiting, restlessness, heart palpitations and even death.

Apple Cores: The core of an apple (as well as plums, peaches, pears, and apricots) contain cyanogenic glycosides. If ingested, dogs can experience dizziness, seizures, collapsing, hyperventilation, and shock.

Macadamia Nuts: The exact chemicals found in macadamias that cause a toxic reaction to dogs is still unknown. If eaten, dogs can develop weakness in their hind legs, vomiting, tremors and hypothermia.

Bacon: Bacon and other foods rich in fat can lead to pancreatitis in dogs causing their pancreas to become inflamed and stop functioning correctly.

Onions: If dogs consume onions it can damage their red blood cells. This causes them to become weaker and move around less. If they consume enough onions a blood transfusion could be necessary.

Garlic: Since garlic is part of the onion family it’s even more dangerous to dogs than onions per ounce. Garlic will turn dog’s urine orange to dark red and like onions, a blood transfusion might be required in severe cases.