The German football federation (DFB) said yesterday that the former Bayern Munich forward, who now plays for Bochum in the Bundesliga, tested positive for a stimulant at an indoor tournament in Leipzig on 5 January.
Wohlfarth, a former leading goalscorer in the German First Division, is the first player to face proceedings in Germany for drug abuse, although other former professionals have admitted to doping in the past.
The 31-year-old forward, who recently returned to play in Germany from the French club St Etienne, has admitted that he had taken the appetite suppressant Recatol, which contained the banned stimulant Norephedrine.
"We were informed on Friday," the Bochum coach, Klaus Toppmoller, said. "The news has hit us like a bomb - It was stupid of him.
"Roland Wohlfarth should have got some information from the doctor about the drug in question."
While admitting to taking the suppressant, Wohlfarth said he did not know that he was taking a banned substance. "It was a shock for me when I got the result of the test. I did not know what I was taking," he said.
Following a major debate about the misuse of drugs last year the DFB has increased its drugs-testing programme and is carrying out random tests at indoor tournaments for the first time as well as testing during training in the First and Second Divisions.
The Bundesliga is taking its traditional winter break and most clubs are currently involved in indoor tournaments.
Wohlfarth faces a ban of at least four weeks. It is unclear how severe the punishment meted out by the DFB will be on the player since there are no similar incidences of drug abuse in the German game to which officials can refer.
Doping has become a major controversy in the game in recent months after the Argentinian player, Diego Maradona, was banned after testing positive for drugs at last year's World Cup finals.
Last month the England international midfielder, Paul Merson, of Arsenal, admitted to using cocaine as well as being an alcoholic. Merson was admitted to a rehabilitation clinic although he has not been charged with any offence by the Football Association. He has just resumed training with Arsenal but has not yet played in a match.
In Germany the former national team goalkeeper, Toni Schumacher, caused a furore when he wrote a controversial book containing doping accusations in the game. Last year a former Bundesliga player also admitted to taking drugs over a long period.Reuse content