Two Red Sox minor-league players have been suspended 50 games for drug use. Miguel Pena (or Mickey Pena, depending on who you ask) was suspended for a "drug of abuse," while Gerson Bautista was suspended for the use of Stanozolol.
Pena was at High-A Salem, and had thrown 13 innings there with seven strikeouts, three walks, and a 3.46 ERA. He was drafted in the sixth round of the 2011 draft by the Red Sox, and while a starter now, likely has a future in relief. He won't get to work on that career path for quite some time, however. What the "drug of abuse" was is not known, but suspensions for this sort of thing are a lot easier to push through for non-union minor-league players than they are for a major-league player, and in some cases, it can make it sound a whole lot worse than it is.
For example, say Pena was busted for smoking marijuana -- if the Red Sox placed him on the 40-man, they could have the suspension voided due to the nature of differing rules between non-roster minor-league players and those on the 40. They won't put Pena on the 40, but the rules allow it -- this is simply meant to highlight the fact that something as minimal as marijuana can earn a minor-league player a serious suspension. It's because, thanks to the union, players on the 40-man roster aren't even tested for something like marijuana.
Of course, we don't know if it was weed, so consider that more instructional than apologetic -- we'll leave the speculating on just what it was for someone else, and let you know later if the actual substance is reported. If you're curious about what it could be, though, under the rules of the CBA, then Sox Prospects' Matt Huegel has the info: it's marijuana, cocaine, LSD, opiates, ecstasy, GHB, or PCP. Not quite as catchy as a Queens of the Stone Age song, but informative nonetheless.
As for Bautista, a right-handed pitcher from Boston's Dominican Summer League team, he was busted for a synthetic anabolic steroid. It's FDA approved, but it's a banned substance in baseball, and that's the overarching law for the game.