We don't generally think of medicine as being very relevant to Steampunk, but it was a big part of Victorian science fiction. Notable examples that you may be familiar with would be Frankenstein and The Strange Case of Dr. Jekyll and Mr. Hyde.
However, in an era in which the science of medicine was making leaps and bounds, medicine appeared in all sorts of science fiction of the time, including The Island of Doctor Moreau, The Invisible Man, and the lesser-known The Lifted Veil by George Eliot.
What do those all have in common?
You guessed it, they're all kind of horrifying. Not horrifying in the sense that they're bad, but horrifying in the way we describe the horror genre today; terrible things happen to the people involved in the stories.
Many of the above stories have become classics over the years, so I suspect that most people reading this article are familiar with them. Thus, let me get right to the chase:
The Victorians were terrified of medicine.
Frankenstein was about galvinism, a property of electricity that many thought could bring the dead back to life. Playing with life and death didn't end well for Dr. Frankenstein.
Dr. Jekyll effectively dies at the end of Jekyll and Hyde, and we can assume that Hyde does as well, though it happens off-screen.
Moreau is killed by his own creations, and Griffin, the invisible man, is effectively driven mad by his transformation.
The Lifted Veil is the only science fiction/horror story that George Eliot, famed realist novelist, ever wrote, and it tells the tale of Latimer, a man who can see into the future. It doesn't end well for him, but a particularly horrifying scene right before the end involves Latimer's doctor friend returning a dead woman to life using a blood transfusion.
None of these examples worked out especially well for anyone involved, and they played upon the fears of the public to great critical acclaim.
So what does this say about Steampunk medicine? Well, the most important thing we should talk about is transhumanism.
Transhumanism is essentially a philosophy that advocates using technology to enhance the human condition; performance-enhancing drugs, cybernetic limbs, and more.
If you look at the above stories that I mentioned, you'll notice that only one of them, The Lifted Veil, is using medicine to cure someone of something. Instead, they're pushing the boundaries of humanity by giving life to creatures, or boosting their own abilities.
As such, it seems to me as though Steampunk medicine should fall firmly under the transhumanist umbrella, and it frequently does. You can already look at Steampunk and see people with steam-powered limbs, crazy vision-enhancing goggles, and who knows what else.
So Steampunk medicine isn't really about fixing what's wrong with you, because that's boring! What fun is a doctor who simply cures you when you're sick? It's far more entertaining to think about a doctor who's pushing the boundaries of humanity, and trying to fix you even though you aren't broken.
There are a lot of people out there sporting the enhanced arms or legs, but hardly any people playing the doctors doing the enhancement! Let's see some more Steampunk doctors, am I right?
Meanwhile, don't forget about potions and chemicals such as those used in Jekyll and Hyde. They're very appropriate for the genre, and can provide some extra points of interest in your costuming!
But when you deal with Steampunk medicine, don't forget the law of unintended consequences...