Whenever I read anything about the medical practices of prior ages, I’m struck by the fact that so many of the medicines prescribed were basically forms of poison: compounds of mercury, lead, arsenic, etc. I suppose it’s true that the “dose makes the poison,” and that most modern medicines are poisonous too, if taken in big enough doses. Still, I wonder about the original line of reasoning that would say that lead, for example, while known to be a poison, had therapeutic value. Does anyone have any insight about this?
Arsenic, taken in small doses, has a stimulant effect. Salts of mercury, while toxic, also have valid medical uses, remember merthiolate and mercurochrome? While the placebo effect, no doubt, played a major role, not all the old medecines were completely useless.
WAG - substances with poisonous properties were an obvious first choice for early herbalists to ‘experiment’ with… between an urge to understand the nature of death, practical efforts to establish survivable dosages and find antidotes… and the simple fact that obviously they were capable of doing SOMETHING. Subtler drugs would be harder to tinker with, on some levels, because it would be hard to tell that they were capable in fact of doing anything.
Does that make any sense?
All medicines are poisonous, in the sufficient dosage.
Sure, but there’s still a big difference between camomile and calomel. I continue to be a little puzzled by the mental leap people made when they said, “Well, we know it’s poisonous, but let’s try just a little and see if it cures you.” Were they onto a real pharmaceutical principle there, or was it just the kind of thinking alluded to by chrisk? But also, it seems evident in retrospect that the practitioners of the day weren’t that sophisticated about dosing, so how did they have any confidence about the threshold between a therapeutic dose and a fatal dose?
I think there are several reasons.
- Most diseases e.g. syphilis were not curable as they had no true antibiotics. However, some of the very toxic medicines e.g. mercury would have some effect on the bacteria. Thus by dosing yourself close to death you may have a chance of a cure.
- As life was short and brutal and no real records kept no one knew whether it was the disease that killed you or the doctor
- Toxic medicines at least produced an effect on the body. The doctors could then point to the effect and say - look the medicine is doing something. If the patient then died it was the disease that was blamed.
Yes.
The poisons, obviously, altered the way the body functioned.
So, a little bit might alter body functions slightly.
As in “non-fataly”.
Pretty obvious, really.
You have succinctly described homeopathy.
How so? Homeopathy is a bunch of bullshit about how the more something is watered down, the more affective it is. In this case, we’re talking about a SMALL dose of something that in LARGER doses could be poisonous, but a small bit won’t hurt.
For example-take one pain pill, fine. Take a whole bottle-emergency room.
And according to Homeopathic principles, rinse out the pill-bottle with fifty litres of water, drink a teaspoonful of that, and you’re BETTER than fine… 
Completerly overlooking the fact that there are trace chemicals in the water, from pipes/processing/pollution, too.
Non-fatally does not mean good. The natural inference is that if a significant dose of poison will kill you, a smaller dose will only make you sick – an inference that is mostly correct, I think. So I’m still wondering why poison = medicine in so many cases, ancient and modern.
That was already answered. In the case of bacterial infections, a little poison has a greater effect on the bacteria than it does on you. For things like pain relievers and stimulants, a little has the desired effect while a lot is fatal.
Yep. Many illnesses resolve regardless of (despite) treatment. Think influenza, for instance. Doctors dispensed meds “back in the day” and when the patient improved, the doc took credit. Many of the medications contained small quantities of digitalis, ipecac, etc. These substances probably did little good, but the patient “felt something” and therefore they assumed the medication was working.
Those old-time doctors were pretty deadly. My favorite story was about the final treatment of George Washington. George was out in the winter cold, and caught a cold, which turned into brochitis. His doctor dosed him with some assorted poisons, and finally BLED the poor guy. Washington succumbed to the “treatment” and closure of the throat, due to bronchitis. Sadly, there was a physician nearby who knew how to perform a tracheotomy (that would have allowed Washington to breathe), but his attending physician didn’t know about it.
Dctors were pretty bad up intill about the 1890’s when they finally were persuaded to wash their hands, sterilize instruments, etc.
That, I think, was where the reasoning started. Take a lot, death. Take a little, better. So, obviously, the less you take the better! (Which often tended to be true, taking none of the medicine was the best way to go.)
You’ve just explained homeopathy in a nutshell, and people still believe that.
I suspect the “it had an effect” suggestion is a significant part of the answer. By modern standards, purgatives were a large part of the market. Get the patient to throw up or loosen their (quite possibily constipated) bowels and they might well have been impressed by that alone. Where detailed (but biased - it’s the hypocondriacs who write this stuff down) records of peoples’ intake survive, we see that they were consuming all sorts of combinations in massive quantities. Medicines that just “cleared the system” might have been helpful.
Nor was it the case that people were completely oblivious to poisonous side effects. Mercury as a treatment for syphilis was a pretty effective, if nasty, remedy in its day. Yet it was also recognised as a poison, with the effect that the great sales pitch if you were a an 18th century quack seems to have been a cure for the disease that didn’t involve mercury. That doesn’t suggest a customer base necessarily merrily dosing themselves on whatever.
As for homeopathy, that’s a relatively late entry into the field, only being proposed in 1796. By then, most of the features of 19th century popular quack medicine were firmly in place. It’s thus probably marginal as an answer to the OP.
In addition to the foregoing, medicine was not very scientific back in the middle ages and early modern period. People believed in the nonsense about ‘humors’ for a very long time, and tailored their treatment to fit the dogma instead of the patient at hand. The people who were dosing with the precursors of modern medicine were the herbalists, and knowing too much about herbs in the wrong place and time could get you branded a witch.