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The "Moon Doctor of Berlin" Who Claimed To Cure People With Lunar Rays


Dr. Katie Spalding

Katie has a PhD in maths, specializing in the intersection of dynamical systems and number theory.

Freelance Writer


A small child "taking their medicine". Image credit: vovan/

Like so much of history, the late eighteenth century was a bad time to get sick. Go to a doctor and you could expect little in the way of working medicines and way higher than ideal levels of being made to puke, poop, and bleed yourself healthy – at least, healthy enough to say “thank you, doctor, I think I’m better now, please stop.”

So it’s not surprising that people turned to alternative therapies – after all, they probably couldn’t be worse than what the doctor would prescribe. This was the age that spawned homeopathy, chainsaws being used for childbirth, and injecting the children of your servants with infected pus (though, to be fair, that one worked).


And in Berlin, one man "cured" people with the moon.

“Doctor” Weisleder, as he called himself, was a one-time sockmaker who worked out of a dingey tavern in the German capital (you might have thought this would raise some suspicions, but it wasn’t much earlier than this that people could get an arm amputated by the same guy who cut their hair, so maybe people were ok with the idea of getting a beer during a medical appointment.) He claimed to be able to cure the incurable, and he was wildly popular, drawing crowds of hundreds to his boozy practice.

His treatment was as simple as it was universal: whatever the ailment, Weisleder would instruct the patient to extend the body part that was affected toward the moon while he mumbled an incantation too quiet to make out. This treatment (for want of a better word) would need to be repeated for three consecutive nights while the moon was in its first quarter, according to believers, sometimes for months on end – a length of time you may recognize as “long enough for most illnesses to either clear up on their own or kill you.”

The fact that so many people entrusted their health to Weisleder and his lunar panacea is all the more impressive when you find out that Mrs Weisleder was doing the same thing at the other end of the tavern. The moon doctor himself would treat male patients by sticking their poorly bits out of the north-facing window, and his wife did the same with female patients at the south-facing window, implying either that the lunar rays weren’t doing much after all or that eighteenth-century Berlin had an extra moon on the other side of the sky that everyone has since forgotten about.


But not everybody in the past was a complete sucker, and the main reason we know about Weisleder is because he got debunked. Marcus Herz, one of the most renowned doctors in the city, was so annoyed by the Weisleder’s popularity that he decided to investigate for himself, writing a long essay titled “Pilgrimage to the moon doctor in Berlin”.

Saying that he was suffering from gout, Herz visited Weisleder’s tavern to see the so-called doctor and his methods. He described Weisleder as gaunt and ugly, and suggested that he might have been transformed into a doctor by an overabundance of “formidable” digestive wind, which is an impressively fancy way to say “talking out of his ass”.

Although we may look at the moon doctor of Berlin today in disbelief, his treatments were no more bizarre than many other practitioners of the time. His ideas on the healing power of the moon sticking bits of your body out of windows at night may have gone out of fashion, but his contemporaries like Samuel Hahnemann or Franz Mesmer left an impact that can still be felt today.

So perhaps that’s the lesson we should take from Herr Weisleder: that as smart and evolved as we think we are, humanity is still just as gullible as ever.

 This Week in IFLScience

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