Before we get into how to cut onions without crying, let's discuss why onions make us cry in the first place. As onions grow they absorb sulfur from the soil and convert it to amino acids. When their cells are damaged (i.e., when the onion is sliced), those acids come into contact with enzymes that catalyze a series of reactions that eventually lead to the release of a volatile chemical compound called syn-propanethial-S-oxide that makes your eyes sting and water. (Sulfur absorption is also at the root of onions' distinct flavor and odor aromaâit's not all bad!)Â Okay, so thatâs the science (lite), but what are the solutions? Well, there are two major strategies: You can stymy the release of the chemical compound, or you can protect your eyes. (Or, when you're really afflicted, you can do both.)