mythbuster graphic A lack of safe drinking water is a common result of disasters, natural or otherwise. But some people argue that even in such situations we have plenty to drink, as long as we don’t turn up our noses at it. Squeamishness aside, is it safe to drink your urine?

With several caveats and under certain conditions, yes, it is safe to drink your urine.

Evidence for the Health Claim

Drinking urine when no other liquid is available—particularly fresh, safe drinking water—may be a matter of survival. Urine is largely comprised of water that has been filtered through the body as part of the body’s ongoing process of flushing out waste products. Although few people like the idea of drinking urine, fewer would prefer to suffer the ultimate consequences of dehydration.

But what about the use of urine as a medicinal substance in well-hydrated individuals?

Many ancient medical and cultural practices in places such as Egypt, China, India, and the Aztec empire, consider drinking urine—one’s own or someone else’s—as a treatment or cure for a variety of ailments.

Even today there are number of alternative medical practices based in the teachings of Ayurveda that allow for urine consumption. Ayurveda, the ancient holistic healing system of India, is grounded in a spiritual view of life. Its practitioners have advocated urine therapy as a treatment for asthma, arthritis, allergies, acne, cancer, indigestion, migraines, wrinkles, and a host of other conditions.

Although no medical evidence supports urine as an effective treatment for any of these (or other) illnesses, scientific studies have shown that some components of urine have medicinal properties. Most notably, urea (which, next to water, is the primary component of urine) possesses antibacterial, antifungal, and antiviral characteristics. And, it should be noted that research is underway to investigate the potential of other urinary substances to treat infertility and specific forms of cancer.

While urine’s purported healing properties have yet to be confirmed by rigorous research, drinking small amounts of your own urine is unlikely to produce serious harm if, for some reason, you are so inclined.

Evidence Against the Claim

Although sipping the occasional urine sample may not be immediately harmful, it should not be forgotten that urine can contain harmful substances in those who have taken drugs—legal or otherwise—or have been exposed to chemical residues in the environment.

Also, if a person were to drink his own urine as a substitute for fresh drinking water, the proportion of water content would rapidly decrease as the proportion of harmful waste products increased.

Urine therapy advocates who tout urine’s healing properties point to the fact that urine contains vitamins, hormones, proteins, and other constituents generally accepted as beneficial. However, detractors point out that the body’s process of elimination is more than merely efficient, ridding itself of what it can’t store. Rather, the kidneys diligently retain what is useful and dispose of everything else deemed dispensable.

Even urine therapy advocates warn of the dangers of excessive urine consumption. During a worldwide conference of urine therapy practitioners, the Chinese Association of Urine Therapy warned that drinking urine has negative side effects, including diarrhea, fatigue, fever, and muscle soreness; and these symptoms increase with the amount of urine ingested.

Conclusion

Because urine is primarily water, drinking it in small amounts is probably harmless unless you’ve been exposed to medications or environmental toxins that your body is desperately trying to eliminate. When faced with life-threatening dehydration, drinking urine may make some sense, since the temporary benefits are likely to outweigh the risks. However, this last ditch effort will be short-lived, since the kidneys stop making urine as the dehydration worsens.