Two Aviva Premiership players tested positive for cocaine last season.
The Rugby Football Union announced the violations of its illicit drugs policy in its anti-doping annual report, published on Thursday.
Alongside its main work looking at performance-enhancing drugs, the governing body has run a testing programme aimed at detecting the use of recreational substances since the 2008/09 scandal at Bath. That resulted in four players being banned, including England prop Matt Stevens who admitted to taking cocaine.
The RFU performed 386 tests for illicit drugs in 2015/16, the majority of them on hair samples that allow detection for up to five months after a drug was ingested.
As they were first offences, the players have not been named but they were fined and sent to a specialist centre for expert assessment.
The total of two positives is the same figure as the season before, and down on the four and five cases from 2013/14 and 2012/13 respectively.
In a conference call with reporters to discuss the RFU's annual anti-doping report, where cocaine was confirmed as the drug in question, anti-doping manager Stephen Watkins said: "While we can never rule it out, we feel pretty confident we don't have some of the issues which maybe occurred in the past."
Phil Winstanley, rugby director at Premiership Rugby, said: "Unless it's being used in competition, cocaine isn't a performance-enhancing drug. Clearly we don't want it in our sport, and that's why we are doing the programme."
On the subject of performance-enhancing drugs, Watkins and Winstanley were equally adamant rugby union can be considered a clean sport, with only four positives from 1,001 tests last season.
That represents a significant rise in the number of blood and urine samples taken from players at all levels of the game – 282 more than in 2014/15 and almost double the figure from 2013/14.
Most of this increase came at the elite end of the game – England's international players were tested 360 times last term, up from 135 a season before – because of the Rugby World Cup in 2015 and build-up to last year's Olympic Games.
In the foreword of the report, the Rugby Players' Association director Richard Bryan wrote: "Given the impact of doping on the wider sporting landscape, it is reassuring to see another season concluded with no indication of systemic doping or illicit drug use among the elite player population in England."
As in previous seasons, the four positive tests came from outside the elite game in what the RFU refers to as "community rugby" – three of these were for steroids and one was a refusal to supply a sample, which counts as a positive test under World Anti-Doping Agency rules.
While four positives from 1,001 tests would seem to support the view that rugby union can consider itself clean, there are still some areas of concern.
The far smaller Welsh Rugby Union accounts for 11 of the 52 athletes currently banned by UK Anti-Doping, with the RFU contributing seven. That means rugby union is responsible for more than a third of the active suspensions.
Another concern would be the fact one of last year's positives, as in previous seasons, came from an unnamed under-18 player. Several anti-doping experts have pointed out how unusual it is that rugby union's doping problems seem to stop when players reach the top of the sport.
But perhaps the biggest worry would be the admission there are still players in the Premiership who can go an entire season without being tested, as only 241 tests were specifically done at this level.