Health & The body: Studying Spanish in Spain is good for your health

Bad Health

Estar pachucho [Familiar] Lit. To be somewhat sick/ill.

Estar hecho polvo [Familiar] Lit. To be rendered into dust. To be really tired or in a bad physical state.
Warning! Don't confuse with "echar un polvo" [Vulgar], literally to throw a piece of dust, which means to have sexual intercourse.

Good Health

Estar como un cañón [Familiar] Lit. To be like a canon. To be in great health and full of energy.
Example: Desde la operación está como un cañón [Familiar] Since the operation he's as good as new.

Ser mano de santo [Familiar] Lit. To be a saint's hand. You can use this expression to refer to something that has done you a lot of good.
Example: El anís es mano de santo para el estómago [Familiar] Aniseed is a miracle cure for the stomach.

Estar vivo/a y coleando To be alive and kicking. In Spanish, instead of kicking, to be wagging your tail is used.

Sano/a como una manzana [Familiar] Lit. To be as healthy as an apple, i.e. to have very good health.

The Body

El tarro, el coco [Familiar] Lit. The jar, the coconut. Both mean the head.
Me duele el tarro [Familiar] My head hurts.

Comerse el tarro/el coco [Familiar] Lit. To eat your jar/coconut. Figuratively speaking it means worrying thoughts are eating away at your brain.
Example: No me comas el tarro con tus historias [Familiar] Don't bug me with your tales.

En pelotas/En pelota picada [Familiar] Literally "in balls". Butt naked.
Example: Abrió la puerta en pelotas, ¡imagínate! [Familiar] He opened the door butt naked - imagine that!

La jeta [Familiar] Literally, the nose of some animals, but in human slang, the full face. Also used to indicate that someone is cheeky, a smart-ass or someone that takes advantage of situations often.
Example: Y no ha vuelto a pagar, ¡qué jeta tiene! [Familiar] And she hasn't paid again, the nerve!

Las patas [Familiar] Lit. Legs of an animal or an object. For comic effect it can refer to a person's legs.
Example: Llevo todo el día andando. ¡Tengo las patas rotas! [Familiar] I've been walking around all day. My legs are broken!

La panza [Familiar] Lit. An animal's belly. Used to refer to the well-rounded human variety - hence Sancho Panza's name in Don Quixote.