have a strong stomach

1. To have the ability to eat foods that others may find unusual, unpalatable, or too spicy without experiencing any ill effects like nausea or upset stomach. My husband has such a strong stomach that he can eat a ghost pepper and feel perfectly fine afterward. You must have a strong stomach if you're eating pickles with peanut butter! Because I know I don't have a strong stomach, I will not be partaking in any of that spicy food, thanks.

2. To have the ability to experience or witness something unpleasant without becoming upset, nauseous, or squeamish. That horror movie you're going to see is pretty gory. I hope you have a strong stomach! I don't have a strong stomach around blood, so I could never be a surgeon. Young William has never had a strong stomach, so I'm not surprised he vomited at the sight of blood.

have a strong ˈstomach

not feel sick or upset when you see or do unpleasant things: You’ve got to have a strong stomach to watch animals being killed.