Cutting an onion breaks its cells, mixing enzymes that produce *syn-propanethial-S-oxide*. This volatile gas reacts with the moisture in the eye, forming diluted sulfuric acid that irritates the cornea.
Cutting an onion breaks its cells, mixing enzymes that produce *syn-propanethial-S-oxide*. This volatile gas reacts with the moisture in the eye, forming diluted sulfuric acid that irritates the cornea.
