The Daily Mail calls scopolamine "the most dangerous drug in the world. " And for once they may have a point. Columbian criminals secretly slip the odourless, tasteless hallucinogen to their victims, turning them into "complete zombies" with "no recollection as to what happened". The sinister substance was also used by the CIA in Cold War interrogations, with the hope that it would act like like a truth serum.
Now German toxicologist and opera fan Professor Hans H. Maurer believes that scopolamine could have been the active ingredient in Isolde's love potion and Siegfried's Gibichung drink too.
Scopolamine causes memory loss, and, says the Prof, 'eroticising' effects are frequently seen. That would account for the consequences of drug-taking in Tristan and Götterdämmerung: forgetting past and duty, falling instantly in love.
But how would Isolde and Hagen have got hold of the powerful toxin? Far from being a modern invention, scopolamine occurs naturally in members of the nightshade plant family, such as belladonna, henbane and mandrake - all of which your average 11th century poisoner could have located readily. Indeed documented use of the drug goes back as far as history itself.
Perhaps the 'potion scenes' aren't the limp, implausible plot devices usually assumed, after all.