Five players at English Premiership clubs tested positive for recreational drug use during the 2012/13 season, the Rugby Football Union (RFU) announced Tuesday.
The third annual doping report by the RFU, the English game's governing body, said 345 tests took place as part of the illicit drugs programme, which conducts out-of-competition tests for common illicit drugs, focusing on Premiership players.
Five positive results were returned.
However, these cases were treated confidentially as they were initial offences, resulting in a 'first strike' fine of £5,000 ($8,000) and access to assessment, rehabilitation and counselling.
"The five players who returned positive tests belong to Premiership clubs," an RFU spokesman told Britain's Press Association wire service.
It is the first time since the illicit drugs programme was introduced for the 2009/10 season there have been violations of the policy.
Four major illicit drug groups are tested -- cocaine, cannabis, ecstasy and amphetamines.
"A small number of adverse findings via the illicit drugs programme is a reminder that we can never assume the anti-doping job has been 'done'," Rugby Players' Association rugby director David Barnes said.
In addition to the illicit drugs programme, there were a total of 617 in and out-of-competition tests for performance-enhancing drugs.
All five of the positive tests for the 2012/13 season in that category were recorded by players at clubs below Premiership level and their cases have already been made public.
No Premiership player has yet to return a positive test for performance-enhancing drugs.
"It is reassuring to see another season concluded with no systemic doping amongst the senior elite players in England. They continue to be role models for the wider game," Barnes said.