Intestino vs. tripa
While both words relate to the digestive system, the main difference lies in the register and versatility. Intestino is the accurate anatomical term used in medical contexts, whereas tripa is a colloquial term that ranges from meaning "gut" or "intestine" to "belly" or even food ingredients like sausage casings.
Intestino
B1This is the formal, scientific term for the bowel. You should use intestino when speaking with a doctor, discussing biology, or describing health conditions related to the organ itself.
El médico me explicó que el intestino delgado absorbe los nutrientes.
(The doctor explained to me that the small intestine absorbs nutrients.)
El estrés puede causar inflamación en el intestino.
(Stress can cause inflammation in the intestine.)
Es importante beber agua para limpiar el intestino regularmente.
(It is important to drink water to cleanse the bowel regularly.)
La bacteria vive naturalmente en el intestino humano.
(The bacteria lives naturally in the human gut.)
Tripa
B2This is an informal word used in everyday conversation. Tripa can refer to the specific organ (guts), the abdominal area in general (belly/tummy), or animal intestines used in cooking (tripe or casings).
Me duele la tripa por comer demasiados dulces.
(My tummy hurts from eating too many sweets.)
Se le notaba la tripa debajo de la camisa ajustada.
(His gut was noticeable under the tight shirt.)
Me rugen las tripas de hambre.
(My guts are growling from hunger.)
Para hacer salchichas caseras necesitas tripa de cerdo.
(To make homemade sausages you need pork casing.)
Tuvo que hacer de tripas corazón y saltar al agua fría.
(He had to pluck up courage and jump into the cold water.)
Summary
Use intestino for biology, anatomy, and serious medical discussions. Use tripa for casual conversation about stomach aches, pointing out a beer belly, or talking about culinary ingredients like sausage skins.