MLS announced the suspension on Friday. The MLS players union appealed, but the suspension was upheld.
Chicago defender Lovel Palmer was also suspended two games for violent conduct toward Portland's Maximiliano Urruti.
Dempsey's action came in the 40th minute of Toronto's 2-1 victory. Dempsey hit Bloom in the stomach/groin area, a blow that was not seen by officials but was captured by television cameras. Dempsey said after the match that he was trying to slap Bloom's hand off his back and did not intend to strike his body.
Dempsey will be eligible to return April 5 when Seattle faces Portland.