Fruit seeds and pits- contain cyanide, which can cause vomiting, excessive drooling, lethargy, and death.
Onion powder, garlic, garlic powder, & onions - large amounts in the diet causes hemolytic anemia from the sulfoxides and disulfides in the onion and garlic. Remember that some soups and baby foods have onion and garlic powder in it.
Caffeine- accelerates heart rate and can cause arrhythmias and seizures. Dog breeds prone to cardiovascular problems are especially at risk.
Avocado - are very high in fat, which can cause pancreas problems. Avocados also have persin in them, which is highly toxic to dogs and causes heart and lung damage.
Chocolate - theobromine &/or xanthine are a components of chocolate. Different brands, types (milk, dark, etc) have different amounts of the compounds , but the more the chocolate has the more toxic it is to the dog. It causes anything from diarrhea & hyper excitability to coma or death. The compounds also have a diuretic effect that can cause dehydration.
Macadamia nuts- the exact toxicity has not been discovered but, they can cause fever, vomiting, abdominal pain, swollen limbs, muscle weakness, and paralysis in the hind legs. In most dogs the paralysis has not been permanent.
Nutmeg - has been known to cause seizures and heart attacks. In large quantities nutmeg is a hallucinogenic
Grapes and raisins- causes vomiting and diarrhea and can progress to kidney failure. The exact toxin is unknown.
Sugar free candies and gums- xylitol is a sweetener used in many candies and gum. It can cause hypoglycemia , seizures, and over a prolonged period can cause liver problems.
Broccoli- isothiocyanate in broccoli can cause severe gastrointestinal upset and if the dogs diet is greater than 25% broccoli, it is fatal.
Animal bones - can cause gastrointestinal obstruction or laceration.
Milk products - some dogs do not have a sufficient amount of the stomach enzyme lactase (breaks down lactose in milk products.) Causes diarrhea, gas, vomiting.
Raw eggs- contain an enzyme, avidin, that decreases the absorption of vitamin B. Vitamin B deficiency causes stunt growth and coat/skin problems.
Yeast dough- expands and causes gas, pain, and could cause an intestinal rupture.
