It's already bad for your cardiovascular system. It's food as a mouth wash but don't swallow it, especially at the recommended doses of 3+ mouthwash per day with 3-5g each time
The recent study on it gave the subjects a 300mL "standardized, artificially sweetened beverage containing 30g of xylitol diluted in water."
Recommended amount is 5–10g per day (5 pieces of 100% xylitol gum, 36% is already effective), taken after meals.