That’s just one example of the many surprising insights urine can reveal about our health and habits. “If you consume alcohol, there are signature molecules in the urine,” says Joshua Coon, a professor of chemistry at University of Wisconsin-Madison. “If you have coffee, we can see a signature of that.” Certain kinds of brain tumors even leave telltale traces in urine before they might be discovered by other means, says David Wishart, a professor at the University of Alberta who has pioneered the study of molecules in urine and maintains a database of more than 3,000 molecules discovered in human urine. Advances in basic research are revealing that “there’s gold,” he muses, “in that gold-colored fluid.”