There was no trace of the drug GHB in the blood of three students who reported becoming ill in a bar during a ski trip to the French resort of Risoul, RTL Nieuws has quoted local officials as saying.

Rumours had been circulating about people being drugged with GHB at the bar, which the owner had staunchly denied.

However, all the students had been drinking heavily, officials said. As yet, they have not said if other drugs, such as cannabis or cocaine, were found in their blood.

Several students from fraternities attached to Utrecht, Leiden, Maastricht, Leeuwarden and Nijmegen were reportedly taken ill on different nights at the resort, causing one group to return home early.

The symptoms included collapsing, the shakes, emotional shifts, memory loss and panic attacks, reports stated. The initial reports also suggested several students had been hospitalised.

RTL said that four cases were known to the police. One girl was checked over by ambulance crew but refused to go to hospital and three students from Rotterdam and Utrecht reported to the police the next day, stating they had been taken ill.