It might give them an upset stomach, it is not best for young children to have fluoride. They sell toothpaste for kids w/out fluoride, I would use that.
Take a trip to your local drug store and ask the pharmacist to help you find a toothpaste specifically made for children (which is safe to swallow.) There is such a thing!
Fluoride-free toothpastes should be given to young children instead, to avoid their swallowing fluoride when brushing their teeth. There are some brands out there like Colgate, Aquafresh or natural toothpaste.
You will find childrens tooth paste at nearly any store. It usually has cartoon characters on the tube and it will say that it's for young children. The fruity flavored toothpaste is okay if they accidentally swallow it in small quantities.
Most of young children eat toothpaste when they brush their normal toothpaste there is enough fluoride which is very harmful for infants,kids and young children.Enamel saver toothpaste is safe for all children.It does not contain any synthetic detergents which can injure on gums.By useing this paste children can be safe.