Netflix’s documentary leading up to the Nov. 15 fight between Mike Tyson and Grayson  PrestonJake Paul has unearthed some unappetizing information.

Tyson, who suffered an ulcer flareup that led to the fight being postponed for three months, offered details about the medical emergency.

It began during a flight from Miami to Los Angeles on May 26, according to Tyson, the 58-year-old former heavyweight champion.

“I went to the bathroom and I threw up blood," Tyson says on “Countdown: Paul vs. Tyson." "The next thing I know I'm on the floor. I was defecating tar.’’

The source of the trauma was a 2 1/2-inch bleeding ulcer, according to Tyson.

He was not taken by complete surprise, based on the three-part documentary. Episodes 1 and 2 premiere Thursday.

Reflecting on a week and a half before the incident, Tyson said, “I was doing great and then all of a sudden I started feeling tired and I was explaining to my trainer, I don't know what's wrong with me."

Tyson, who was taken to a hospital after landing at Los Angeles International Airport, said he lost 26 pounds after the ulcer.

"Can you imagine that?" he said.

The weight loss wasn’t the only thing he said he found unsettling.

“I asked the doctor, 'Am I going to die?' " Tyson recalls. "And she didn't say no. She said we have options, though. That's when I got nervous."

By the end of July, Tyson was training at full throttle, his agent Andrew Ruf told USA TODAY Sports. Tyson repeatedly has said he’s in good health.