'Guatitas' is the Chilean word for tripe, a diminutive of 'guata,' the everyday Chilean word for belly.
Diced beef tripe is stewed with potatoes, onion, and a deep-red ají sauce until thick enough to eat with a spoon and bread. It's sold by the bowl at northern Chile's covered markets, usually alongside rice.
Why it's made this way: The dish reflects Arica's long-standing Peruvian and Aymara culinary overlap, where tripe stews spiced with ají are everyday market fare rather than special-occasion cooking.