strong stomach

Example: After a night out at the bars, Juan consumed a cheese steak, a slice of pizza, a milkshake, and several chocolate brownies; it was only his strong stomach that allowed him to keep it all down.

Example: The emergency medical technician was glad for her strong stomach when she came upon the car accident victim's body.

Example: "One with a strong stomach and a hard head may be able to tolerate much of the unconscious and undeliberate cruelty and torture of the world that is perpetrated in hot blood and stupidity." (from Jack London's Michael, Brother of Jerry).