Swimming's world governing body Fina has become the first international sports federation to sign up to the World Anti Doping Agency's new code.
The code allows for greater flexibility and discretion to be used.
It will be especially relevant in cases where medicines such as asthma inhalers or decongestants have been used.
"Sometimes two years wasn't enough, sometimes it was too harsh. Things will now be done on a case-by-case basis," said Wada lawyer Richard Young.
"Rules are rules and people should expect consequences for their actions.
"The old code worked well, but there wasn't so much leniency and there were instances of unfamiliarity."
Under the revised code, which comes into force in January 2008, athletes testing positive for Wada's "specified substances" can avoid or reduce their sanctions by demonstrating how they were not at fault or did not intend to enhance their performance.