Onions not only add wonderful flavor to food, they also offer significant health benefits. According to the Academy of Nutrition and Dietetics, high concentrations of allyl sulfides in onions do double duty fighting heart disease and cancer. Onions are a source of inulin (for a healthy gut), and a good source of vitamin C, fiber and manganese.
If cooking with onions brings tears to your eyes, here's why according to the University of Illinois Extension: When you cut into an onion, the cell walls are damaged releasing a sulfur compound called propanethial-S-oxide which floats into the air. This compound is converted to sulfuric acid when it comes in contact with water which is why it produces the stinging sensation and subsequent tears.
To reduce tearing when cutting an onion, the National Onion Association recommends you "first chill the onions for 30 minutes. Then, cut off the top and peel the outer layers leaving the root end intact." It's the root end that has the highest concentration of the sulphuric compounds that cause your eyes to tear.
If you still have problems with tearing, consider purchasing pre-chopped onions. If a sweet onion will work in your recipe, sweet onions may be less likely to make you cry.
The article was originally written by Alice Henneman. It was reviewed and updated in 2021.