Roberto Carlos has strenuously denied allegations made by German TV network ARD that he took illegal stimulants.
A documentary aired by the ARD network claimed that the World Cup-winning full-back was named in a document given by Brazil's anti-doping agency to prosecutors in Sao Paulo in 2015.
But, in a post on his official Facebook page, the former Real Madrid star denied the claims, and promised to take legal action.
"I strongly reject the irresponsible accusations made by the German ARD network," Carlos' statement read.
"I reaffirm that I have never used any device that would allow me to take advantage of my colleagues.
"The report quotes the name of a doctor I never knew in my life, and my lawyers have been called to uphold the alleged false allegations in the matter.
"At the same time, the story states in an extremely vague way that I was seen in his office in July 2002, when I returned to the country after the World Cup with the Brazilian National Team.
"I went to Brasilia to participate in the awards ceremonies and, soon after, I returned to Madrid, in Spain, without any passage through Piracicaba. In addition, the report does not reproduce any evidence of my alleged involvement in the case.
"Throughout my career, I have always advocated fair play. The lying accusations against me are completely contrary to this thought.
"In more than 20 years of my career I have never tested positive for any substances that would change my performance."
Carlos won La Liga four times as well as three Champions League titles in an 11-year playing career at the Santiago Bernabeu.