I hate to sound like a Philistine, but his work sounds rather ... inaccessible (my emphasis):
Mr. Muehl’s art had clear affinities with the action painting of Jackson Pollock and the body art of performers like Chris Burden. (In a famous piece from 1974, Mr. Burden had himself crucified, with real nails, atop a Volkswagen Beetle.)
But to judge from his vast portfolio, Mr. Muehl out-Burdened Burden for violence and out-Pollocked Pollock for viscosity.
Yes, Mr. Muehl splattered his nude subjects with paint in live performance and on film, but he also splattered them with soup, juice, milk, egg whites, blood, the internal organs of freshly slaughtered animals and, in a coup de grâce that appeared to follow the foodstuff to its inevitable conclusion, fecal matter.
It should also be noted that Mr. Muehl’s subjects, far from being idle, were, per his carefully worked-out choreography, generally having sex at the time.
Or, Mr. Muehl's work could be downright dangerous:
To judge from the periodic bans imposed by the Austrian authorities, Mr. Muehl’s art was sometimes considered a threat to public morality; at other times it was simply considered a threat to public safety. He was once arrested and briefly jailed for a performance that entailed throwing a kitchen sideboard stuffed with flour and marmalade out of a window. Whether any injuries ensued is unrecorded.
I think Mr. Muehl may have said it best:
“I enjoy confounding people. That is my big idea. I have nothing more.”