The Rugby Football Union (RFU) announced on Tuesday that five players at English Premiership clubs tested positive for recreational drug use during the 2012/13 season.
The third annual doping report by English rugby'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 - cocaine, cannabis, ecstasy and amphetamines - focusing on Premiership players.
The five cases of positive results were treated as confidential as they were first-time 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 the 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.
"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," said Barnes.