19th-Century Doctors Prescribed a Dangerous Douche: Liquid Mercury

Medically Reviewed by Melinda Ratini, MS, DO on July 12, 2023
4 min read

The “cure” was often more horrifying than the disease – because the cure was mercury, one of the most well-known toxic substances in the world.

In the 1800s and early 1900s, doctors often prescribed mercury for syphilis and other venereal diseases. It was an ointment; it was added to vapor baths; it was even used as a vaginal or urethral douche.

Patients dabbed it on their sores or inhaled it. Doctors administered it using a device made by a French instrument-maker: a receptacle for holding the liquid mercury compound, with a green hose and attachments of various sizes for insertion into the vagina or urethra.

The resulting symptoms – excessive cramping, salivating, diarrhea, and vomiting – were violently unpleasant. But for many 19th-century doctors and patients, that was how they knew the treatment was working.

At the time, many doctors still believed in the humoral theory of disease, dating back to Hippocrates, several centuries BCE. The idea was that the human body held a mix of four humors, or fluids: black bile, yellow or red bile, blood, and phlegm. Disease meant the humors were out of whack; purging was thought to bring them into balance.

Syphilis, which affected 10% of England’s population at the end of the 19th century, has a cycle of remission and recurrence, so what looked like a cure was often just a temporary respite. That could make it hard to tell what was actually helping, what was hurting, and what was only an illusion. Meanwhile, mercury-treated patients were dying.

The “irritating effect” of douching with the mercury-containing compound was noted in a 1910 article with the unsparing title, “Poisoning by Mercuric Chloride through Vaginal Douches,” published in the Journal of the American Medical Association. The physician author chronicles one particularly grisly case: a 35-year-old woman who sought medical care after 4 days of persistent vomiting.

Over the next several days, she vomited blood, fell into a stupor, and developed kidney failure. She died 1 week after consulting the doctor.

A 1916 article in the British Medical Journal, “Perchloride of Mercury Poisoning by Absorption from the Vagina,” told the story of a 27-year-old woman who douched with mercury perchloride tablets dissolved in water, then placed one tablet directly into her vagina. The article described her pain, swelling, cramping, diarrhea, and persistent vomiting, followed by kidney failure. She died 6 days later.

“It is evident that the absorption of the poison in toxic quantities must have taken place through the vagina,” wrote the author of the 1910 article. “This case … ought to constitute a warning to physicians that mercury can hardly be employed with safety in this manner.”

But that didn’t stop doctors from prescribing it.

Mercury has a long history of medicinal use – and an equally long litany of devastating side effects, according to Lydia Kang, MD, assistant professor of general internal medicine at the University of Nebraska Medical Center and author of Quackery: A Brief History of the Worst Ways to Cure Everything.

Teething powders containing calomel, also known as mercurous chloride, was sold until 1948; it caused a condition called pink disease in babies: icy, swollen, red, and intensely itchy hands and feet.

Mercury-laced “cures” for melancholy, constipation, influenza, and parasites caused an illness known as mercurial erethism. Often called mad hatter’s disease after the 19th century haberdashers who caught it from exposure during the felting process, mercurial erethism is a neurological disorder characterized by tremors, anxiety, pathological shyness, and frequent sighing.

“Mercury became a catch-all medicine to purge in all these different ways,” Kang says. For syphilis, “they felt like it was doing something as opposed to nothing.”

Patients who inhaled or consumed mercury suffered the most toxic effects, Kang says; a douche meant a smaller, shorter-lasting exposure. But repeated or highly concentrated use could be fatal.

Salvarsan, an antimicrobial agent developed by a Japanese professor in the early 1900s, and penicillin, introduced as a treatment for syphilis in the early 1940s, changed the game. But mercury treatment persisted for so long not only because of the absence of more effective cures, says Kang. It was also the result of a stubborn mindset.

“There were people who were pretty logical saying, ‘I think the medicine is making me sicker than the syphilis,’ but their voices got drowned out. Status quo is very hard to change in the absence of information that can convince an entire population and an entire generation of medical workers to change their minds.”