The majority of injuries were caused by the indomitable Gauls (87.1%), with Asterix and his large sidekick Obelix themselves responsible for more than half (57.6%). Only 32 head injuries were caused by Romans, write the researchers, led by Marcel A Kamp from Heinrich Heine University, and just one by a pirate. Although 70.5% of the victims were wearing a helmet, this was lost "in the vast majority of cases", while "a doping agent called 'the magic potion'" was found to have been taken by the perpetrators of 83% of the injuries. "This substance contained mistletoe and was believed to give superhuman strength. In fact, characters who took the magic potion before traumata caused significantly more severe traumatic brain injuries," the academics discovered. They note that a component of mistletoe, lectin, has been shown to have effects on brain tumours, but say that its role in the treatment of traumatic brain injuries "needs to be clarified by further studies".