Xylitol is a sugar substitute that can be found in sugar-free candy, chewing gum and other products. While in humans xylitol has no effects on the level of blood sugar, in dogs it is a strong promoter of insulin and it can cause severe hypoglycemia with ataxia, collapse and seizures. Xylitol can also cause hepatic necrosis and death. One or two pieces of gum are enough to cause hypoglycemia in a 22 lbs dogs.
The toxic agent in anti-freeze is ethylene glycol, and it is found in most commercial antifreeze preparations. Because of its sweet taste, antifreeze toxicity is a common problem in pets. As much as a teaspoon in a small cat, or a tablespoon in a small dog can prove to be lethal. Clinical signs can occur as early as 30 minutes after ingestion and consist of ataxia and vocalization, progressing to increased breathing and heart rate, and ending in acute renal failure and death.