Terrifying Ways Scientists Used Themselves As Test Subjects Throughout History

Throughout history, some scientists have pushed the limits of knowledge not by experimenting on others, but by turning themselves into the test subject. Whether out of desperation, stubbornness, or sheer curiosity, these researchers took risks most people wouldn’t dream of. In many cases, their methods would never pass an ethics board today, but their self-experimentation helped change the course of medicine, biology, and psychology.

Here are some of the most jaw-dropping examples of scientists who put their own bodies (and lives) on the line for discovery.

Barry Marshall drank bacteria to prove a theory.

In the early 1980s, Australian doctor Barry Marshall was convinced that stomach ulcers were caused by a bacterium called Helicobacter pylori, not by stress or spicy food as many believed. His peers didn’t take him seriously, and he struggled to prove it through animal testing.

So he did something drastic: he drank a beaker of the bacteria himself. Within days, he developed gastritis, proving that H. pylori could indeed infect the stomach. He then treated himself with antibiotics and recovered. His work eventually earned him a Nobel Prize in 2005, and changed how ulcers were treated around the world.

J.B.S. Haldane repeatedly subjected himself to pain and injury.

British geneticist and physiologist J.B.S. Haldane was known for his brilliance, and for his willingness to endure physical harm in the name of science. In the 1930s, while studying the effects of extreme conditions on the human body, he volunteered himself for high-pressure experiments.

During one of these, designed to simulate the effects of deep-sea diving, the intense pressure caused a crushing headache and burst his eardrums. Haldane shrugged it off, saying, “The drum generally heals up.” His work laid the foundation for safety in submarines and high-altitude aviation, but at serious personal cost.

Werner Forssmann shoved a catheter into his own heart.

In 1929, German doctor Werner Forssmann wanted to show that a catheter could be safely inserted into the heart through a vein—a risky and widely dismissed idea at the time. So he ignored hospital protocol, strapped his own arm to a board, and inserted a catheter into a vein in his elbow.

With the tube in place, he walked to the radiology department and took an X-ray to prove it had reached his heart. He was later fired for his stunt, but the medical world eventually caught up with him. He won the Nobel Prize in 1956 and is now considered a pioneer of cardiac catheterisation.

Stubbins Ffirth tried to catch yellow fever on purpose.

In the early 1800s, American medical student Stubbins Ffirth believed that yellow fever wasn’t contagious. To prove it, he conducted a grim series of tests on himself using bodily fluids from infected patients—blood, vomit, saliva, even urine.

He smeared it into cuts on his arms, rubbed it in his eyes, and even drank it. Thankfully for him, he didn’t get sick. Unfortunately, his conclusion was wrong: yellow fever is contagious, but it’s spread by mosquitoes, not fluids. Ffirth’s experiments were horrific, but they reflected the lengths early researchers would go to try and solve medical mysteries.

Max Joseph von Pettenkofer swallowed cholera.

In 1892, German chemist Max von Pettenkofer doubted that cholera was spread purely by germs in water, as proposed by rival Robert Koch. To challenge this, he drank a solution containing live cholera bacteria.

Amazingly, he didn’t get seriously ill, though some historians suspect he had partial immunity, or that the bacteria had weakened. While his theory didn’t stand the test of time, von Pettenkofer’s stunt is still remembered as one of the boldest acts of self-experimentation in medical history.

Jonas Salk injected himself with the polio vaccine.

When Jonas Salk developed his inactivated polio vaccine in the 1950s, it had to be tested before going public. But rather than wait for approval or experiment on children, he and his team started with themselves and their families.

Salk injected himself, his wife, and his children with the vaccine to show his confidence in its safety. This early step helped pave the way for widespread trials and ultimately led to one of the most successful vaccination campaigns in history. You can read more on this from the World Health Organization.

John Paul Stapp pushed his body to the brink.

US Air Force officer and flight surgeon John Paul Stapp was determined to understand how extreme acceleration affected the human body. In the 1950s, he strapped himself into rocket sleds designed to test the limits of human endurance in high-speed crashes.

Stapp was subjected to forces of over 40 Gs—more than what astronauts experience during liftoff. He broke bones, suffered temporary blindness, and was battered by bruises, but he kept going. His work directly improved car safety and pilot survival techniques.

Albert Hofmann took the first LSD trip… on himself.

Swiss chemist Albert Hofmann accidentally absorbed a small amount of LSD-25 while synthesising it in 1943. Curious about its effects, he decided to take a full dose—250 micrograms—and document the experience.

He rode his bicycle home while under the influence, reporting intense hallucinations and sensory distortion. The event, known as “Bicycle Day,” became the first recorded LSD trip. While Hofmann didn’t expect it to spark a countercultural revolution, his self-experiment opened the door to decades of research into psychedelics and the brain.

Henry Head cut his own nerves.

British neurologist Henry Head wanted to understand how nerves regenerate after injury. So he and a colleague decided to sever the radial and external cutaneous nerves in Head’s own arm in 1903.

Over several years, he meticulously documented the gradual return of sensation—pain, temperature, touch—all from personal experience. His research was groundbreaking and shaped neurology for decades. But it came with serious long-term consequences, including lasting damage to his arm.

Vladimir Demikhov created two-headed dogs.

In the 1950s, Soviet scientist Vladimir Demikhov conducted controversial organ transplant experiments, including attaching the head and forelegs of one dog onto the body of another.

While he didn’t experiment directly on himself, Demikhov tested all his methods in his own lab, under intense scrutiny and danger. His work was widely condemned at the time for being cruel and gruesome. Yet it paved the way for modern organ transplant techniques, including heart and lung transplants.

Why self-experimentation still matters (and why it mostly stopped)

These examples might sound reckless, and they were, but they often came from a place of genuine dedication to understanding the human body and saving lives. That said, modern science has (thankfully) moved on. Ethics boards, peer review, and stricter regulations now exist to prevent unnecessary risks and protect people, including researchers themselves.

Still, the legacy of these experiments lingers. Some of the biggest breakthroughs in medicine and biology were sparked not in laboratories with double-blind trials, but by someone willing to put their own body on the line. It’s a reminder of how far science has come, and how much some gave to get us here.