Five Mexico internationals have tested positive for the banned substance Clenbuterol.
The players named are goalkeeper Guillermo Ochoa, defenders Francisco Rodriguez and Edgar Duenas and midfielders Antonio Naelson 'Sinha' and Christian Bermudez.
Mexico are taking part in Concacaf Gold Cup in the United States.
Despite the controversy, Mexico booked their place in the quarter-finals on Thursday with a 5-0 victory over Cuba.
"We will wait for the final result [of the investigation]," said Mexico coach Jose Manuel De La Torre after the game.
"Not having all the players hurt but we will be waiting for Concacaf's decision."
The general secretary of the Mexican Football Federation (Femexfut) Decio de Maria said the quintet had been suspended from the tournament.
He added that any further sanctions, which could include bans of up to two years, would be determined by Femexfut.
"Late on Wednesday we received the anti-doping analysis of 14 players of the 'Tri' [national team] that were done on 21 May and five players showed positive," De Maria announced at a news conference.
"The substance for which they were positive is Clenbuterol. The players will be withdrawn from coach Jose Manuel de la Torre's team."
De Maria added: "The cause is believed to be because of [eating] beef or chicken between 17 and 20 May so an investigation will be made with the food suppliers. For the time being we don't see any negligence by anyone, not even theirs.
"We know there is a health alert throughout the country because of food contaminated with Clenbuterol and that will be taken into account for the investigation."
In April, Germany's anti-doping agency [Nada] advised against athletes eating products from Mexico because it might increase the risk of involuntary positive doping results. Mexico denied there was a problem.