how many people left CBS survivor for medical reasons?

Answer 1

Three.

-Michael Skupin was airlifted from camp in Australia due to severe burn injuries. A Tribal Council was held in his absence but never broadcast.
-Bruce Kanegai was rushed to a Panama City hospital on Exile Island due to severe pain from a blocked colon and bladder, and did not return to the game, leading to his elimination. He was still able to participate in the jury.
-Gary Stritesky of Fiji fell down hard in a reward challenge, and faced an unhealthy condition and was forced to leave the game.