Urine

Urine, colloquially referred to as piss or pee, was a substance that Oswald Danes claimed was put in his food in jail. Although they covered it with things like cream and gravy, he could still taste the urine, for, as he put it, "[piss] has a way of enduring". (TV: The New World)

Samantha Jones' friends Mo and Mikey Clunes were locked up overnight for urinating on the front window of Woolworths. (PROSE: Kursaal)

Somerset's genetically enchanced leopards could record information that could later be read from their urine. (PROSE: Alien Bodies)

The Seventh Doctor once urinated in a linen store and "realised that the shelf he was peeing over was an inch deep in dust" (PROSE: Delta and the Bannermen (novelisation)

In a timeline created by Faction Paradox, Sarah Jane Smith "had to take a pee behind someone's house" in the town of Anathema on the planet Dust. She doubted that anyone there would have cared if they had seen her in the act, and noted that "she'd never had to think about these little biological details on most of the planets she'd been to." (PROSE: Interference: Book One)

A woman in a Cardiff shop, when questioned by the Torchwood team as they tried to track down Bernie Harris in 2007, said she "wouldn't even piss on him if he was on fire". (TV: Ghost Machine)