Toothpaste is not considered safe for small children. If small children are brushing their teeth with toothpaste, it is recommended to not use more than a pea size of toothpaste with fluoride. If you are using a toothpaste without fluoride, still check the ingredients to see if it contains anything that could be harmful. Tooth paste was meant to be spit-back out, not swallowed. Most small children do not understand this concept. The fluoride in toothpaste is considered poisonous if ingested in any considerable amount. It should be kept out of reach of children and pets.
If you think you child has ingested toothpaste, call poison control.