Fluoride is safe and effective in controlling tooth decay when used properly. However, too much of anything can be bad and that the same with fluoride. Children should use toothpaste with fluoride, but for young child they should be supervise by an adult.
Children under the age of six are more likely to swallow toothpaste after brushing instead of spitting it out. You want to make sure they only use a pea-sized amount of toothpaste when brushing their teeth. Encourage your child to spit out and rinse as much as possible. Avoid flavored toothpaste with younger children as it may encourage swallowing or eating of the toothpaste.