Doukara was hit with the suspension by the Football Association tonight over an incident in the second half of a 1-1 draw between Leeds and Fulham at Elland Road on February 23.
The Frenchman was accused of biting Amorebieta in the 54th minute of that game and saw a charge of violent conduct upheld by an independent regulatory commission.
Doukara had denied the claims against him and pleaded not guilty to a breach of FA Rule E3.
His ban will come into immediate effect, ruling him out of United’s trip to Rotherham United on Saturday and forcing him to miss all but one of Leeds’ nine remaining Championship games.
Doukara will return to contention for the club’s last fixture of the season at Preston North End on May 7.
On top of his suspension, he was fined £5,000 and warned by the FA about his future conduct.
The governing body has not yet published the commission’s written judgement but in a short statement it said Doukara’s offence was “considered a non-standard case given the seriousness and both unusual and violent nature of the misconduct.”
Leeds said they were unable to comment fully until the full reasons for the verdict were released. A statement from United read: “Suffice to say the club is disappointed with the outcome and the length of the ban given to Souleymane Doukara.”
Doukara and Amorebieta are believed to have clashed as Leeds defended a cross from the left wing as Fulham attacked towards Elland Road’s South Stand shortly after half-time.
Doukara was not punished at the time by referee Kevin Wright, who later sent off Amorebieta for a second bookable offence in injury-time.
The FA’s punishment of Doukara effectively brings to an end a campaign which came to life for him around Christmas.
The former Catania forward - a maligned figure in periods of his two-year career at Elland Road - ended a 12-month goal drought by producing a flurry of four strikes in six games after the turn of the year.
He has been a regular in United’s line-up during the second half of the season, starting all of their last 16 games.
Head coach Steve Evans was approached for comment but did not respond.