For millennia, healers used their eyes, noses and, yes, even their palates to diagnose patients. Physicians from as early as 1500 BC used urine to detect diabetes, for example, by observing that ants were attracted to the sugar in the patient's pee. Today, we'd probably be more likely to diagnose the disease using a blood test, but urine can still provide valuable information—including, for instance, if you aren't drinking enough water.
According to a study published in The Journal of Pediatric Gastroenterology, urine's chemistry can indicate your diet and the state of your health. Urine's pH can reveal whether you are dehydrated; a high concentration of salts can signal an illness like diabetes; and a bluish or greenish color may mean you are taking certain drugs, such as methylene blue (used in some tests).
The article goes on to report that urine can also give a clue to the state of your metabolism. "Urine can have a sweet, fruity or salty taste," it says. It also can be a little metallic. In a case of severe dehydration, urine can even be bitter and smell like bile.
While it's not a good idea to drink your own urine in normal circumstances, some people do. Actor Sarah Miles, for example, claims that a clinic in California cured her allergies by having her drink a glass of urine every day. And reclusive author JD Salinger, who wrote the classic Catcher in the Rye, reportedly practiced urine therapy as well.