9 Intriguing Truths About Urine

Urine, often overlooked, is a remarkable substance with a variety of unexpected applications and characteristics. David Bowie famously stored his in the fridge. During World War I, soldiers in Ypres used urine-soaked socks as makeshift gas masks to shield themselves from chemical attacks. This pungent, water-based fluid, rich in urea, can range in color from pale yellow (based on hydration levels) to green or orange (due to certain medications). Discover nine fascinating ways urine has played a role in human history.

1. For over two millennia, urine has served as an effective antiseptic.

In ancient times, before the advent of modern medicine, urine was a lifesaving remedy for minor injuries that could otherwise prove fatal. Pliny the Elder advocated its use for ailments like scorpion stings, snake bites, rabies, burns, and skin sores. He even proposed a mixture of aged urine and roasted oyster shell ash as a remedy for infant skin rashes.

During the Renaissance, Leonardo Fioravanti, an Italian physician, observed a Spanish soldier lose his nose in a fight. Fioravanti urinated promptly on the severed nose and then reattached it surgically to the soldier’s face. In 1675, The Accomplish’d Lady’s Delight in Preserving, Physick, Beautifying, and Cookery recommended washing one’s face with urine to achieve a fair complexion. (A writer tested this in 2016, yielding inconsistent outcomes.)

Urine possesses antibacterial properties directly linked to urea concentration, its primary metabolite [PDF]. Higher urea levels enhance its antibacterial effectiveness. While factors such as urine osmolality (how diluted it is), pH, and ammonium concentration also play a role, urea remains the key component.

2. The Romans used urine to wash their garments.

Urea breaks down into carbon dioxide and ammonia, the latter responsible for urine's strong odor. Ammonia is a key component in many modern cleaning products, which is why aged urine was widely used as a laundry detergent in the Roman Empire. By the 1st century CE, containers for gathering urine were placed at street corners, outside inns, and in Roman baths. Emperor Vespasian even levied a tax on urine collection. Some fullonicae (Roman laundries) sourced their urine directly from public urinals through pipes.

At the fullonicae, urine was left to ferment for three days before being poured into vats filled with dirty laundry. Fullones (launderers) would stomp on the mixture to remove dirt, then rinse and dry the clothes.

3. Fertility drugs derived from two hormones found in urine were developed with assistance from the Vatican.

In the 1940s, Piero Donini, a scientist at the Italian pharmaceutical firm Serono, isolated two hormones, FSH and LH, from the urine of post-menopausal women. In 1957, endocrinologist Bruno Lunenfeld collaborated with Serono to conduct a clinical trial to determine if these hormones could treat infertility. The main obstacle was obtaining the vast quantities of post-menopausal urine required to extract enough hormones.

Fortunately, the Vatican, a major shareholder in Serono, stepped in. Through Don Giulio Pacelli, the Pope’s nephew and a company director, Pope Pius XII persuaded Italy’s postmenopausal nuns to donate their urine daily for a noble cause. Nuns across Italy contributed their urine, enabling Serono to develop the fertility drugs Pergonal and Menopur, which are still in use today.

4. Urine played a pivotal role in fueling wars for centuries.

Gunpowder consists of 75 percent potassium nitrate, also known as saltpeter, 10 percent sulfur, and 15 percent charcoal. Until the mid-1800s, saltpeter was either imported from India or produced locally using aged urine. Geologist Joseph LeConte outlined the process in his manual Instructions for the Manufacture of Saltpeter. Urine from humans and animals was collected in nitre beds, mixed with lime and wood ash. The potash in the wood ash provided potassium to form potassium nitrate. The mixture was stirred occasionally and left to decompose for about two years [PDF], after which it was filtered and crystallized to obtain saltpeter.

Europe’s frequent wars created a high demand for urine to produce gunpowder. In 1625, England’s Charles I tasked saltpetermen with extracting urine from stable floors, and in 1627, he issued a royal decree urging citizens to collect urine in "suitable containers." A saltpeterman named Nicholas Stephens gained notoriety for excavating church floors, claiming that “the earth in churches is best … for the women piss in their seats, which produces excellent saltpeter.”

Even in 1865, during the final stages of the American Civil War, women in the Confederate states were urged to save their urine as a desperate measure to replenish ammunition supplies.

5. In ancient Egypt, urine was used to detect pregnancy—and even predict the baby’s gender.

The earliest known DIY pregnancy test is documented in the Berlin Papyrus from 1350 BCE. It instructed women to water wheat and spelt seeds daily with their urine. If both grew, she would bear a child; if only wheat grew, it would be a boy; if only spelt grew, a girl. If neither grew, she was not pregnant. Modern experiments in 1963 confirmed a 70 percent accuracy rate [PDF]. Urine from non-pregnant individuals or men failed to germinate the seeds. Surprisingly, the first at-home pregnancy test wasn’t available until 1971.

6. Phosphorus was discovered by an alchemist experimenting with aged urine.

In 1669, Hamburg physician Henning Brandt attempted to create the “philosopher’s stone” by mixing sand, charcoal, and distilled, decayed urine. Instead of gold, he produced a glowing, soapy substance he named “cold fire.” Later known as phosphorus, from the Latin for “light bringer,” Brandt kept his discovery secret.

Around a decade later, renowned English chemist Robert Boyle developed a more efficient method to extract purer, solid phosphorus from urine (Brandt’s method had only produced 120 grams from a staggering 5500 liters of urine). Boyle’s assistant, Ambrose Godfrey, advanced the research by extracting phosphorus from animal feces. Godfrey was far from squeamish, sourcing it from the excrement of horses, cows, sheep, cats, dogs, lions, tigers, bears, mice, rats, chickens, and fish.

Another 17th-century chemist, while extracting phosphorus from urine, found that rubbing it on the genitals caused inflammation and a burning sensation. It’s unclear what prompted him to test this.

7. Urine is a key component of a seasonal Chinese delicacy.

In Dongyang, China, locals celebrate a seasonal dish called Virgin Boy Eggs. Each spring, vendors collect urine from boys under 10 to create a broth for marinating and cooking eggs. The eggs are boiled in the urine, their shells cracked, and then simmered in the liquid for an entire day. Vendors replenish the urine to maintain heat and sometimes add herbs and spices. The final product features green yolks and pale golden whites. Locals believe it enhances blood circulation, prevents heat strokes, and revitalizes the body.

8. The world’s first penicillin dose was derived from urine.

On March 12, 1942, Anne Miller, a 33-year-old septicemia patient at Yale-New Haven Hospital, became the first person treated with penicillin. At the time, the antibiotic was not yet approved in the U.S., and production was slow. Miller’s urine played a crucial role in her treatment.

Since 40 to 99 percent of penicillin is excreted unchanged in urine [PDF], Miller’s doctors bypassed synthesizing it from scratch. An intern collected all of Miller’s urine, which was sent to Merck & Co for penicillin extraction. After her recovery, scientists continued harvesting urine from patients until industrial-scale production became possible.

9. Astronauts convert their urine into drinking water.

Human urine is approximately 95 percent water, making it an ideal candidate for recycling, particularly in environments where clean water is limited, such as the International Space Station. On the ISS, the American crew obtains its drinking water by recycling urine and air condensate. Astronauts use a Water Recovery System (WRS), which includes a Urine Processor Assembly (UPA) and Water Processor Assembly (WPA) [PDF], generating around 3.6 gallons of water daily. The Russian crew, however, does not recycle urine directly; they store it in bags and transfer it to the American side for inclusion in the recycling process.

On Earth, the concept of turning urine into drinkable water is gaining momentum. Belgian researchers have created [PDF] a device that utilizes solar energy and a specialized membrane to transform urine into potable water.