Michinori Tanaka fought a fellow star from the Asian circuit in Kyung Ho Kang last September, it was a thrilling bout that stole the show that event. Unfortunately for the Japanese prospect, not only did he lose a close split decision that handed him the first loss of his career, a regrettable decision to take over-the-counter allergy medication prior have now cost him his $50,000 bonus from that night.
Here's the official UFC statement where they also announce his suspension:
UFC bantamweight Michinori Tanaka tested positive for ephedrine and pseudoephedrine based on a pre-fight urine test administered prior to the event. Ephedrine and pseudoephedrine are stimulants banned in athletic competition pursuant to the World Anti-Doping Agency (WADA) code. Based on such results, UFC officials decided that Tanaka had violated his promotional agreement and the UFC Fighter Conduct Policy. Accepting the accuracy of the test result, Tanaka has admitted to taking over-the-counter allergy medication prior to the fight, likely causing the positive result, and acknowledges the illegal substances were in his system. Consequently, Tanaka agreed to a nine-month suspension from unarmed combat competition. He must pass a drug test at the conclusion of his suspension in order to return to competition. Tanaka will also forfeit his Fight of the Night bonus he earned at the event.
Ephedrine and Pseudophedrine are normally used as a decongestant for people with colds, and although their effectiveness as stimulants that improves performance aren't well established, they are still part of the banned substance list.