Harrison was suspended for the first four games of the 2007 regular season for admitting to federal investigators that he knowingly obtained and used human growth hormone (HGH). Harrison stated to the media that he used "a banned substance" for "accelerating the healing process from injuries sustained playing football," and "never to gain a competitive edge." In addition, according to federal agents and Harrison himself, Harrison received a shipment of HGH, with his name on it, just days before Super Bowl XXXVIII in February 2004. Later, he expressed regret over his decision to use the substance calling it "a black cloud over my career." "I played 15 years and that doesn't feel good. That's embarrassing...It wasn't smart. I put a foreign substance in my body and don't know the long-term effects," he said on "Football Night in America".