"The player tested positive for cocaine metabolite benzoylecgonine, a substance included in WADA's 2017 Prohibited List under the class 'S6. Stimulants', following a doping control test conducted after the match," FIFA said in a statement.
"By testing positive for a prohibited substance, the player has violated article 6 of the FIFA Anti-Doping Regulations and, as such, contravened article 63 of the FIFA Disciplinary Code."
Peru qualified for the World Cup finals for the first time since 1982 by beating New Zealand in a two-legged playoff. Guerrero missed both those matches.
His ban will be back-dated to Nov. 3 and will apply to international, domestic and official friendly fixtures.
Guerrero, who used to play for German club Bayern Munich, made his international debut in 2004 and has 83 caps, scoring 32 goals.
He helped Peru finish third in the 2011 and 2015 Copa Americas and was leading scorer in both tournaments.
He also helped Brazilian club Corinthians win FIFA's World Club Cup in 2012, scoring the winning goal in the final against Premier League side Chelsea.
He joined Flamengo in 2015 and has been prolific in front of goal, scoring 42 goals for the Rio de Janeiro club.
(Reporting by Martyn Herman,; editing by Ed Osmond)
