Can You Eat Onions Raw?

Fozia Sherazi, Dr of Dietetics and Nutritional Sciences

Written by Fozia Sherazi, Dr of Dietetics and Nutritional Sciences. Updated on March 12, 2023.

The onion is a member of the Alliaceae family and is classified as a biennial herbaceous plant. Onions are commonly grown as annuals for their bulbs.

The name “onion” derives from the Middle English unyun, which came from the French oignon, which originated from the Latin unio, which means “onion.”

Due to its easy cultivation, the onion has been a part of the human diet for thousands of years.

Onions originated in Central Asia, and it is thought that they spread to Europe and the Middle East. The ancient Egyptians, Greeks, and Romans cultivated them.

Inscriptions and paintings on ancient Egyptian structures attest to the frequent use of onions in ancient Egyptian civilizations.

The ancient Romans spread onions further during the conquest of Europe, and they were widely cultivated in medieval Europe.

By the Middle Ages, onions had become a widely-used culinary ingredient, and they were so highly regarded that they were even used as currency in some places.

Many onion varieties were known in the first century, including long, round, red, yellow, white, spicy, and mild. G

Green onions later on, originated in China.

All the forms that can be eaten have similar tastes and smell that come primarily from volatile chemical compounds.

The distinctive flavor of onions results from the sulfur-containing compounds released when the onion cells are damaged during chopping or crushing.

Alliums are easy to grow and require minimal maintenance, making them popular among gardeners.

Onions can be grown in most soils but are sensitive to waterlogging and thrive best in moist, well-drained soil.

Today, some of these allium plants are grown primarily for their decorative value, while others, such as garlic, leeks, Welsh onions, and chives, are more commonly used as culinary ingredients.

Onions are not only grown for their edible bulbs but also for their leaves, which can be used to add flavor to a variety of dishes.

Onions are versatile culinary ingredients and can be used in various ways, from being eaten raw as part of salads to being cooked and caramelized for sauces and soups.

Can You Eat Red Onions Raw?

Red onions are quite famous for their mild, sweet flavor and vibrant color.

They range in size from medium to large, with deep reddish purple skin and white flesh with a tinge of purple around the edges of their rings.

Red onions are perfectly safe to eat raw; however, they have a slightly sharp flavor compared to other onion varieties.

When eaten raw, red onions can add crunch and a sweet-tart flavor to salads, pickles, sandwiches, wraps, tacos, and more.

To prepare red onions for raw consumption, one should remove the outer layer of skin and cut off the root and stem ends.

After this, slice the red onion in half from root to stem and cut it into thin slices or small cubes.

Then, soak the onion slices or cubes in cold water for about 10 minutes before draining and serving.

This process of soaking red onions helps to take away some of their sharpness while still preserving their crunch and sweet-tart flavor.

Additionally, the length of soaking should be monitored carefully since too long of a soak could result in the red onion becoming too soft and soggy.

After the red onions have been drained, you can use them in salads, sandwiches, or other recipes that call for the ingredient.

To ensure the best results, it is important to use fresh red onions that are free of blemishes and have bright and vivid colors.

Benefits of Eating Onions Raw

Eating raw onions provides several nutritional benefits. Onions contain vitamins and minerals, including vitamin C, manganese, potassium, and iron.

Raw onions are also a great source of dietary fiber, which helps with digestion and gut health. Additionally, raw onions contain antioxidants, which help to protect the body from oxidative damage caused by free radicals.

The following are some of the health benefits of eating raw onions:

Antimicrobial Properties

Eating raw onions is believed to have antimicrobial properties, which can help fight off harmful bacteria and other microorganisms.

Studies have shown that raw onions can inhibit the growth of several types of bacteria, including salmonella and E. coli.

Additionally, research has also indicated that onions may be beneficial in helping to fight off other infections, such as candidiasis and ringworm.

Anti-inflammatory Properties

The consumption of raw onions may also provide anti-inflammatory benefits.

Studies have shown that raw onions contain several compounds with anti-inflammatory properties, such as quercetin and sulfur compounds.

Quercetin, for example, has been shown to reduce inflammation and relieve pain associated with arthritis and other inflammatory conditions.

In addition, sulfur compounds found in raw onions have been found to reduce inflammation in the respiratory system, making them beneficial for those with chronic bronchitis and asthma.

Anticancer Properties

Studies have also found that raw onions can potentially reduce the risk of certain types of cancer, such as colorectal and stomach cancer.

The anticancer properties of raw onions are thought to be due to flavonoids and sulfur compounds.

In particular, the sulfur compounds in raw onions have been found to help inhibit the growth of cancerous cells and protect healthy cells from damage.

Side Effects of Eating Onions Raw

Despite the potential health benefits of eating raw onions, it is essential to be aware of the possible side effects.

Raw onions can cause an upset stomach and heartburn due to their high sulfur content.

Additionally, eating too many raw onions can increase the risk of developing gastritis, a condition in which the stomach lining becomes inflamed.

Eating raw onions can also cause breath and body odor as the sulfur compounds are released through the skin and breathed out.

People with IBS (Irritable Bowel Syndrome) are especially sensitive to the sulfur compounds in raw onions and should avoid them, as they can worsen IBS symptoms.

For these reasons, it is generally advisable to avoid consuming large amounts of raw onions.


Onions are scientifically known as Allium cepa and belong to the Liliaceae family. They are closely related to garlic, chives, leeks, and shallots.

Onions originated in central Asia and have since become one of the most widely used vegetables worldwide.

Many varieties of onions exist, with texture and flavor differences depending on the climate and soil in which they are grown.

They have a characteristic pungent taste and smell, containing certain volatile sulfur compounds. Onions are a key ingredient in many cuisines and can be eaten raw, cooked, or pickled.

Raw onions can have many health benefits, including lowering inflammation, reducing cancer risk, and improving gut health.

Eating onions raw may have undesirable side effects, including bad breath and an upset stomach.

However, these side effects can be minimized by eating smaller amounts of raw onion and ensuring that the onions are fresh and not overly bitter.

How we ensure this article is accurate?
  1. It's written and or reviewed by an expert.
  2. We cite relevant studies and trusted sources.
  3. It's regularly updated.

Read more about our process and team.