Onions are a staple in many cuisines around the world, but their pungent aroma can often lead to tears. The chemical responsible for this reaction is syn-propanethial-S-oxide (SPSO), which is released when the onion’s cells are damaged. When SPSO comes into contact with the eyes, it triggers the release of, which is the body’s natural way of flushing out irritants.
There are a number of things that can be done to avoid crying when cutting onions. One is to cut the onion under cold water. The cold water will help to slow down the release of SPSO, and it will also help to flush away any SPSO that does come into contact with the eyes. Another way to avoid crying is to wear goggles or safety glasses when cutting onions. This will create a barrier between the eyes and the SPSO.