(CNN)If the idea of drinking hand sanitizer, absorbing ultraviolet light and gargling salt water to prevent or treat Covid-19 sounds bizarre to you, know that this isn't the first time humans have put themselves in dangerous situations to quell their fears.
Bloodletting and gas fumes: Quack treatments of the 1918 flu
In the face of threat by a new infectious disease, people become desperate, said Dr. Jeremy Brown, an emergency care physician and author of "Influenza: The Hundred-Year Hunt to Cure the Deadliest Disease in History."
That desperation and a similar threat were what made people living during the 1918 flu pandemic — which killed 50 million to 100 million people worldwide — flock to dangerous quack treatments like moths to flames. That included doctors.
Although conventional doctors had just recently gained more respect than alternative practitioners by the early 20th century, mainstream doctors still "had almost nothing to offer" for the flu said Laura Spinney, a science journalist and author of "Pale Rider: The Spanish Flu of 1918 and How It Changed the World."
Since they thought the 1918 flu was a bacterial disease instead of a virus, their knowledge and treatment efforts fell short, she said.
"Through the course of the pandemic, you see people gradually turning away from conventional medicine as they realize it can't help and turning to the alternatives, folk medicines, quack cures and so on," Spinney said. "Which, of course, until very recently (in the early 20th century), had been equally respectable and equally accessible."
Doctors also "really had no concept of when a medicine becomes a poison — how medicines interact with human tissues and what the right dosing is," Spinney added. Those questions are what "we ask in our clinical trials these days that cost so much, take so long and try to measure safety and efficacy."
Additionally, during the Covid-19 pandemic, "we've talked a lot ... about the importance of trust between people and doctors and public health experts," Spinney said. "But trust also mediates the kind of intimate relationship between a patient and their physician. And it shapes, in a strong way, that placebo effect and hence the effectiveness of any treatment.
"One of the interesting things you see in 1918 is that trust broken down because people saw that their doctors were hopeless. And so they, seeking to control the symptoms, turned to alternative systems which they felt could offer more hope, more effective treatments at that point," she added.
"In different ways, both these pandemics have illustrated to us how absolutely critical to so many aspects of health care — not least, whether people participate in vaccination campaigns — comes down in the end to trust and trust the general public has in their medics and in their governments."
Devastation, desperation and an inexperienced, unregulated medical field constituted a petri dish for numerous unproven — and sometimes barbaric — treatments.
Aspirin, made from the bark of willow trees, had been used to treat pain for millennia. Since aspirin was known for reducing fevers, too, the drug became the international first-line treatment for flu — sometimes administered in doses six times higher than what is now known to be safe, Brown said.
The problem was misunderstanding that aspirin has a "narrow therapeutic window, meaning if you give too little it doesn't work (but if) you give too much, it can cause some very, very dangerous conditions." They include "sweating, ringing in the ears, rapid breathing and then brain swelling and coma, convulsions and death," Brown said.
Given the exorbitant doses and fatal side effects, many flu deaths may have been from aspirin overdoses rather than just the virus itself, some studies have suggested.
However, some countries with death tolls in the millions — such as India — didn't have easy access to aspirin — so it probably didn't have a major impact on the global death toll, according to one study, Spinney said.
Quinine, another centuries-old drug from cinchona bark, has been used mainly for treating malaria, caused by infection with the parasite Plasmodium. Like the flu, a symptom of malaria is fever.
"If you have malaria, you give somebody quinine, you attack the parasite," Brown said. "If you don't understand that the fever goes away because the parasite is killed by the quinine, you miss out that little step and say the fever went away because the quinine, so quinine must be good for all fevers."
Quinine wasn't toxic to the flu virus since the infective agent that caused flu — a virus — differed from the infective agent that induces malaria — a parasite. That modern medicine will test therapies for similar symptoms is reasonable and common, Brown said. "The problem is if you just take a drug used for one condition and you're not testing it to see if it improves a second condition, but you're just simply giving it on the belief that it must, should or will," he added.