• Chiliboy Ralepelle is one of two Boks to be sent home. Picture: AP
The players, Chiliboy Ralepelle and Bjorn Basson, have been sent home, but insist they do not know what made them test positive for methylhexaneamine.
As the two were the only players to be tested after the Springboks' game against Ireland ten days ago, and as no-one was tested after their win in Wales on Saturday, a question mark hangs over the rest of the squad, who are preparing for Saturday's match against Scotland at Murrayfield.
"Two of our players have been found to have a stimulant in their urine after the Ireland game," South Africa doctor Craig Roberts announced yesterday in Edinburgh. "There is a process being followed by the International Rugby Board which we are adhering to - they have to have their B samples tested.
"It can come from a number of different sources. It's actually quite a troublesome stimulant - the literature says from food sources to medicines to supplements. It is quite commonly found in quite a number of things. It's like a caffeine-type substance."
Methylhexaneamine was originally intended as a nasal decongestant, but more recently has been used as a dietary supplement along with caffeine. As a minor stimulant, it has also been used as a component in recreational drugs.
The World Anti-Doping Agency (Wada) only added it to the list of prohibited substances this year, and from 1 January 2011 it is to be downgraded - being reclassified as a "specified stimulant" rather than a banned one, and likely to incur a warning rather than a suspension.
"At this stage we're going through the process on everything they've taken to see if we can identify where it's coming from," Dr Roberts continued. "Quite a few athletes inadvertently have taken it, and that's why it's being moved down to a specified stimulant from 1 January.
"We're looking at the potential areas where it could have come from.
"We do a lot of testing, so it came as a big surprise to us. They (Ralepelle and Basson] were on medication for flu, but we've used it for some time and never had any problem with it. That was the week leading up to the Ireland Test and since then we've been pretty good, not had any sniffles.
"They were shocked. They had no idea where it could possibly have come from."
Basson was due to return home in any case, after spraining ankle ligaments in his team's win in Cardiff. It was decided that, as he faced a rehabilitation period of two to four weeks, there was no point in keeping him in Britain for a tour which has a fortnight and three games to run - against Scotland on Saturday, then against England and the Barbarians on the following two weekends. Ralepelle, however,
had been widely tipped to start against Scotland on Saturday.
Springboks head coach Pieter de Villiers, who was given the news at 2am yesterday, said his squad had been stunned when they were told. "The team were gutted this morning. It came as a surprise to us, because we've been tested throughout the year and we came clean every time. (The players were] definitely shocked.
"We're just worried that something might go wrong from our side. We had a random test of eight players before we came here (ie began the tour] and they were clean. If we find anything wrong we test it, then we go to the next step.
"We're doing everything from our side to clear the whole thing. We're working round the clock now. We're testing everything in our camp, even energy drinks, so we don't make the same mistakes again."
It was the third time Ralepelle had been tested this year. On the other two occasions the tests were negative. Neither player will be replaced.
There have been several high-profile cases involving methylhexaneamine over the past two years. At the Commonwealth Games in Delhi last month, two Nigerian athletes tested positive – Nigerian 100m gold medallist Damola Osayemi and her compatriot Samuel Okon, who was sixth in the 110m hurdles. Also last month, two Portuguese cyclists and nine Australian athletes tested for it.
Nutritional supplements have been found to be the cause in many cases, and are one of the possible factors they will look at. Until they find the cause, they know that every other player in the squad runs the risk of testing positive should he be asked to provide a urine sample after Saturday's game. It is uncertain if anyone will be asked to do so, however, as Six Nations Rugby Limited, the body responsible for doping control in the Autumn internationals in Europe, does not automatically test after every match.
One option for Doctor Roberts and his colleagues would be to test the whole squad, but yesterday he ruled that out for the time being. Instead, the South Africans will await the results of tests on various samples of substances they have sent to laboratories.