What is the fastest growing tissue in the body?

Gums: When you are an infant, nearly all tissues are growing at a fast pace as you grow. Once you're an adult, things slow down. However, the outer layer of your gums grows and is replaced the fastest day-to-day. You can see this if you scratch your gums or burn your palate on hot pizza...it usually heals within just a day or two. A similar injury to your skin or internal organs would take much longer.