The International Paralympic Committee announced on Tuesday that Thomas Oelsener had tested positive for methenolone, a muscle-building steroid.
German team officials said they would fight the decision, with Oelsener claiming he had not knowingly taken the substance.
Oelsener, who won gold medals in biathlon and cross country skiing, became the first athlete ejected from a Winter Paralympics for a doping scandal.
The German team physician Dr Karl Quade said Oelsener tested positive for the steroid after his biathlon victory on Friday, but by Sunday traces of the drug were gone.
This indicated he had consumed a single dose that would not have done him any good, Quade said.