The story of Pocahontas saving John Smith is an often repeated myth that originated with Smith; but has no true basis in fact.
John Smith had a reputation for telling tall tales. He often boasted of having fought Turks in Hungary, of being held as a prisoner of war but escaped by killing his jailer. He also claimed that, in hand to hand combat, he beheaded three Turkish soldiers; a handsome accomplishment to say the least. Smith was exceptionally unpopular on the voyage to America; so much so that he was put in irons while the ship was at sea. Later, when sealed orders from the London Company were opened, it was revealed that Smith was to command the company and the settlers had no choice but to release him and put him in charge.
The incident with Pocahontas did apparently happen; however it was something of a staged event which the Pumunkey Indians performed to demonstrate the power of their chief. Pocahontas, whose name translates to "frisky," and who was about twelve at the time, was only playing a part. At no time was Smith's life in danger.
Smith never told anyone the story until he was back in London some years later. Pocahontas was married to John Rolfe at that time, and accompanied Rolfe to London. She was quite a hit there, and Smith then told the story to anyone who would listen. There is evidence of a meeting between Smith and Pocahontas in London; all indications are that the meeting was quite uncomfortable.