Latrinalia is a type of deliberately inscribed marking made on latrines: that is, bathrooms or lavatory (restroom) walls. It can take the form of art, drawings, or words, including poetry and personal reflections. Other types of latrinalia include political commentary as well as derogatory comments and pictures. When done without the property owner's consent, it constitutes vandalism. Some venues have attempted to curb such vandalism by installing in the restrooms large blackboards and providing free chalk; it is hoped that patrons will avail themselves of the blackboard and chalk rather than applying their latrinalia directly to the walls or toilet stalls.
The late Alan Dundes, a folklorist at Berkeley, coined the term latrinalia in 1966 to refer to graffiti found in restrooms. Dundes preferred it over the term shithouse poetry, as not all latrinalia is in verse or poetic form.
The word is derived from the compounding of latrine (or toilet) and the suffix-alia, which signifies a worthless collection of something — in this case bathroom writings.