Boxing: Tyson admits he was high on drugs during fights

Mike Tyson.

Mike Tyson was high on drugs during some of his major fights and used a fake penis filled with someone else's urine to fool drug-testers, he has admitted for the first time.

The former world heavyweight boxing champion discloses in a new tell-all memoir that he spent a significant stretch of his turbulent career addicted to cocaine and marijuana.

"I was a full-blown cokehead," Tyson says in Undisputed Truth, published this week. Recalling his shock 2004 loss to Britain's Danny Williams, he reveals he was taking drugs until shortly before the fight.

Tyson, now 47 and retired, describes his ferocious appetite for drink and drugs that dated back to trying cocaine at the age of 11 and first being given alcohol as a baby in New York.

He says he was high before a match against Lou Savarese in Glasgow in June 2000 - and came up with an ingenious method to prevent detection.

Confessing that he had taken cocaine and marijuana before the bout, he says: "I had to use my whizzer, which was a fake penis where you put in someone's clean urine to pass your drug test."

He blamed a US$200,000 ($241,000) fine for testing positive for marijuana after a 2000 fight against Andrew Golota in Detroit on the fact that he was tested before having a chance to get the "whizzer" from a member of his team, whom he claims typically carried the device from fight to fight.

Tyson explains that he had taken cocaine before a notorious televised press conference with Lennox Lewis in New York in January 2002, which descended into a brawl.

"I lost my mind," Tyson recalls. "I looked over at him and wanted to hit the mother******."

As the pair of heavyweights tussled, Tyson bit Lewis's leg.

Tyson, the youngest boxer to win the WBC, WBA and IBF heavyweight titles, says he regrets that his drug use led to "Herculean" mood swings.

After years of rehabilitation treatment - between staging a one-man show, appearing in the film The Hangover and socialising with A-list celebrities such as Victoria Beckham - Tyson said in August this year that he was close to death due to his chronic alcoholism.