The Latest NEWS
Why Do Eyes Cry When Chopping Onions, And How Do I Stop It?
We’ve all had the experience: cooking a quick dinner after work, preparing a meal for friends, or throwing together a Saturday morning breakfast, when suddenly you cut into a fresh onion and your otherwise-average day turns into a tear fest. But why do onions so frequently bring us to tears, and what can we do about it?
It turns out, onions make you cry because of a chemical reaction that occurs when you cut them. Inside the cells of an onion, there are two chemicals that are normally separate. Sulfenic acid precursor floats around the cytoplasm of the cell, while a protein called alliinase is sealed in closed bubbles called vacuoles. Normally, the two chemicals don’t come into contact – but if you break the cell open and destroy the vacuoles, they’re allowed to intermingle.
When this happens, the two compounds merge in a chemical reaction that produces lachrymatory factor, or LF. And when LF interacts with air, it releases a gas called propanethiol S-oxide, which has similar properties to tear gas – and this is our culprit. In an intact onion, there’s no danger, but as soon as a cell is broken, the onslaught of tears begins.
How to Stop Crying When Cutting an Onion
So what can you do about the tears? The best option is prevention. Chilling an onion in the fridge or soaking it in water are both effective ways to reduce the potency of the onion, but they can also dampen its flavor. Another folk remedy is to avoid chopping down with your knife, and instead use a back and forth, sliding motion to cut: this can help to minimize the crushing of onion cells and thereby reduce the amount of LF created.
If you’re already in the throes of an onion-induced crying session, your best option is to flush your eyes with clean water or rub a damp paper towel around the area of your eyes. In any case, the problem should alleviate within a few minutes, or at most a few hours – if you don’t, it’s time to call your NYC eye doctor for an emergency appointment.
Schedule an Appointment with Your NYC Ophthalmologist
Have more questions about the effect of onions on eyes or want to schedule an eye checkup? We’d love to help. Call us today at 212.874.2300 with any questions or to schedule a consultation. We can’t wait to hear from you!