Why do onions make us cry?


People cry when they feel sad or overwhelmed with joy. Surprisingly, onion can have the same effect on people. If you are a regular at the kitchen and a food lover, then you may have experienced it too. Sometimes you don’t have to be the one cutting the onion, the onion can even affect a bystander. Thus, in this article, we will investigate why onions make us cry and see if we can find some remedies.


Scientists and doctors advise individuals to take in lots of fruits and vegetables. Many people are ignorant of the fact that onion is a vegetable. Yes! A vegetable. In Ghana, onion is applied in almost every food we make from local to continental meals. Onions can be applied in different forms: chopped, deep-fried, sauteed, they always add a good taste to all our meals.

Slicing, chopping or dicing onions makes food tastier but the process is hard as it usually results in tears, runny nose. The result is worth it.

How onions make us cry

As mentioned earlier, people do not intentionally cry while chopping onions. It comes naturally, a reflex action. This is how it happens:

Onions are bulbs that mature underground. This means that the vegetable is below the surface of the soil. Onions developed an ability to inhibit creatures(animals) that stay underground from eating them. This served as a defence mechanism that protects them and helps them to grow which then becomes available for harvest.

Firstly, onions contain an enzyme(alliinase) and amino acids sulfoxides. When a person slices or bites an onion(in the case of the underground creatures) the enzymes reacts on the amino acid to form an acid- sulfenic acid. This acid is hugely unstable so it rearranges itself to form a gas that can evaporate called syn-Propanethial-S-oxide.

Propanethial S-oxide which is now a gas travels via air to the eyes and other parts of the body. However, it turns into a new acid- sulfuric acid when it touches the water layer that covers and protects your eyeballs. Yes! Acid on the eyes.

The brain (nerves in each eye) recognizes what has happened and immediately stimulate the lachrymal glands (structures responsible for producing tears) which generate tears and flush the acid from the eyes and sometimes the nose.

Fun fact: Onions developed this defence mechanism to prevent underground animals from harming their bulb.

Some people will react more strongly than others. This is termed sensitivity. Hardly, a few people report being allergic to onions. They can have symptoms such as

· Hives- bumped rashes on the skin

· Itching

· Tingling

Does the type of onion influence how much you cry?

The answer is yes! There are several types of onion on the markets. The onions that generate tears have more sulfuric containing compounds. These are usually present in onions that are yellow, red or white. Green onions usually have fewer sulfur-containing compounds and generate the least tears in people.

The question is, “Can we produce onions that do not generate tears”? Scientists have already manufactured such breeds and they are called sunions which are available only on special markets. They are yet to be mass-produced.

Home remedies for onion tears

Since the public cannot have access to these genetically modified onions, we must create means of reducing the tears. Truth is, the onions are not dangerous to the eyes, the eyes have a mechanism of flushing them out. They are just a nuisance when cooking. Nevertheless, if your eyes become itchy or irritated, here are some tips to reduce the irritation:

1. You can physically create a barrier between yourself and the onion you are cutting especially if you are cooking on a large scale.

2. Rinse your eyes with cool and clean water.

3. Place cool cucumbers or a cool compress over the eyes to reduce irritation.

4. Use eye drops that are meant for lubrication to flush out the eyes.

How to prevent crying while cutting onions

One may ask, is there another way to prevent the onion from hurting the eye in the first place? Maybe! Since the gas travels via air, it will eventually get to the eye but certain behaviours can prevent it from happening. It has been realized that how long an onion is stored can affect its tear-producing abilities. Whilst older stored onions cause more tears to be produced, fresher onions generate lesser tears. Below are some behaviours that can prevent crying whilst cutting onions:

· Cut onions properly- Chefs recommend slicing onions away from you so that the gas formed will not rise directly to the eyes. A sharp knife is better as it causes less damage to the onion which will release fewer gases. Lastly, avoid cutting onions at the root end because they contain the highest amount of sulfuric compounds that can generate tears.

· Use cold water- putting onions in water reduces the acid content. This way, no gas will form and no tears generated. Others prefer to cut the onions while submerged in the cold water. This works too but you will cause a splash when you put them in oil whilst wet. Other people find that their eyes get less irritated if they run water while they’re cutting onions.

· Shield yourself from the vapor-You can turn on the fan to allow circulation which will spread the air containing the irritant gas to a different region or probably wear something to protect the eye such as googles. Working under a cooking hood, which supplies ventilation, may also help.

One old tale says to keep a piece of white bread in your mouth while cutting, based on the theory that the bread will absorb onion vapour. There’s no evidence for this, but it’s worth a shot.

The taste onion generates in food is hard to duplicate but if you are having such a hard time, you can always go for something similar. Other vegetables such as radishes, shallot or celery may generate a similar taste. You can also opt for dried onion/onion powder or preferably already precut onions which are both available frozen and fresh.


  1. Healthline. Retrieved from https://www.healthline.com/health/why-do-onions-make-you-cry#prevention
  2. Retrieved from https://www.sciencenewsforstudents.org/article/why-onions-make-us-cry


A young lady who is excited to influence the society and world with the knowledge she has acquired.