After teeing off for the third round, Woods took a swig of water and threw it up as he walked towards the first green.
He was battling illness on Friday as well, suffering from a cough and fever. He looked in poor condition on the driving range prior to teeing off Saturday.
Woods kept going and rallied on the back nine, posting four birdies including three in a row on the last three holes of the day.
"It wasn't easy and I fought hard," Woods told reporters. "That's about all I had."
Woods had no intention of withdrawing from the tournament even though he also threw up before the round.
"I like to compete," he said. "If I can go, I can go. I'll give it everything I have. I wasn't in pain. Just a little bit under the weather."
Despite his ability to rally, Woods is in last place in the tournament and is the only golfer not above par, finishing even after three rounds. The Hero World Challenge is a charity tournament hosted annually by Woods.