Drug cheats will face a minimum four-year ban instead of two years after rule changes ratified by the World Anti-Doping Agency (WADA).
The change to the sanctions, effective from January 2015, will see athletes who take performance-enhancing drugs such as steroids, the blood-boosting agent EPO and human growth hormone face the longer bans, meaning they would miss at least one Olympic Games.
Outgoing WADA president John Fahey, who has been replaced by Craig Reedie - an International Olympic Committee vice-president from Stirling in Scotland, said of the rule changes: “This is a good day for sport.
"We now have a code which, I believe, offers the best response to combating the scourge of doping yet: stronger sanctions while maintaining flexibility, greater investigative powers for WADA, a stronger focus on the sharing of information between the sport movement and governments, intelligent testing and risk assessment and fair consideration of an athlete’s human rights.”
There will be flexibility in the bans for those who fail tests due to taking contaminated supplements.
Meanwhile, concerns have been raised over standards at the testing laboratory in Moscow, which is due to handle samples for next year’s winter Olympics in Sochi.
WADA is holding a hearing to deal with the concerns and the lab could have its accreditation suspended.
Earlier this year WADA stripped the Rio lab of its accreditation and all samples from next year’s football World Cup will be sent to Switzerland for analysis.
WADA’s revised code was agreed at its conference in Johannesburg, and it also gives stronger powers to punish coaches and trainers who help athletes cheat.
Another key change is WADA will now be able to tell sports which banned substances they should be testing for.