Xylitol is an artificial sweetener found in some chewing gums and other sugar free foods. Although safe for humans, xylitol can cause problems for your dog's pancreas and liver. The pancreas is responsible for creating insulin, which triggers sugar from the blood to be stored in the body's cells. When your dog consumes xylitol, the artificial sweetener tricks the pancreas into releasing lots of insulin that is not actually needed, resulting in their blood sugar to drop to dangerously low levels. This can cause seizures, coma and even death. In addition to causing problems with the pancreas, xylitol also causes liver damage and potentially even liver failure. The toxic dose of xylitol is very small, even a stick of chewing gum can be enough to make your dog very unwell.