Dogs should never eat xylitol.
It’s a sugar substitute that’s often found in candy, chewing gum, baked goods and toothpaste. When dogs consume xylitol, it may lead to a rapid drop in blood sugar levels and symptoms like muscle weakness and seizures.
The effects of xylitol in dogs have the potential to lead to more serious complications, such as liver damage and even death.
Source: https://www.healthline.com/nutrition/human-foods-for-dogs#section9