Months after the biggest fight in boxing history, there is still controversy surrounding the Floyd Mayweather Jr. and Manny Paquiao bout. Now, it is being reported that Mayweather used a banned substance prior to the match.

SB Nation reported on Wednesday that Mayweather allegedly took an intravenous injection of saline and vitamins that was banned under the World Anti-Doping Agency’s guidelines the night before he fought Pacquiao.

The report states that when agents with the United States Anti-Doping Agency went to Mayweather’s home on May 1, they found evidence that the banned IV had been injected. Mayweather’s medical team informed the collection agents that the IV, which was administered after the weigh-in, was being given to the boxer for rehydration purposes. Pacquiao, however, who had a shoulder injury which he did not disclose before the bout, was denied an injection with a legal painkiller before the fight.

The bout between Mayweather and Pacquiao took six years to come to fruition and drug-testing was a major factor in holding things up. After the fight, dozens of class-action lawsuits were filed against both fighters by fans who were not pleased with the match.

"The TUE for Mayweather's IV -- and the IV was administered at Floyd's house, not in a medical facility, and wasn't brought to our attention at the time -- was totally unacceptable," said Bob Bennett, the executive director of the Nevada State Athletic Commission. "I've made it clear to [USADA CEO] Travis Tygart that this should not happen again. We have the sole authority to grant any and all TUEs in the state of Nevada. USADA is a drug-testing agency. USADA should not be granting waivers and exemptions. Not in this state. We are less than pleased that USADA acted the way it did."

USDA said Thursday that Mayweather was granted an exemption for the infusion.

The undefeated boxer is set to fight Andre Berto on Saturday in what is believed to be his final bout.

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