A relatively new trend in contemporary art is to use body fluids in art, though there have been rarer uses of blood (and perhaps feces) for quite some time, and Marcel Duchamp used semen decades ago. Examples include:
The controversial Piss Christ (1987), by Andres Serrano, which is a photograph of a crucifix submerged in urine;
Self (1991, recast 1996) by Marc Quinn, a frozen cast of the artist's head made entirely of his own blood;
Piss Flowers, by Helen Chadwick (1991-92), are twelve white-enameled bronzes cast from cavities made by urinating in snow (though this might not be characterized as the use of bodily fluids in art, just their use in preparation);
performances by Lennie Lee involving feces, blood, vomit from 1990
many paintings by Chris Ofili, which make use of elephant dung (from 1992).
Gilbert and George's The Naked Shit Pictures (1995)
Hermann Nitsch and Das Orgien Mysterien Theatre use urine, feces, blood and more in their ritual performances.