The Dodger left fielder will lose about one-third of his $25 million salary.
Ramirez issued a statement through the Major League Baseball Players Association saying he recently saw a physician for a personal health issue who gave him a medication which he thought was OK.
Ramirez is the third player suspended this year under the major league program, following Philadelphia reliever J.C. Romero and Yankees pitcher Sergio Mitre.
Just two relatively low-profile players were suspended under the major league program last year, San Francisco catcher Elizier Alfonzo and Colorado catcher Humberto Coto.
In the past, the best-known player penalized was Baltimore's Rafael Palmeiro, who received a 10-day suspension in 2005, the first year of penalties for first infractions.