Does Garlic Work as a Natural Antibiotic?

Garlic antibiotic

The phrase “garlic – nature’s antibiotic” does not seem to be just organic hippie propaganda. Multiple studies have shown garlic to be effective in treating bacterial infections, yeast overgrowth, and parasites.

Antibiotics were a revolutionary health invention in the 20th century. Nowadays they are widely overprescribed and the risks involved in their use are not properly understood. In the United States, 40% of all adults and 70% of children take antibiotics every year. (1)

This is alarming given that just one course of antibiotics has the potential to permanently disrupt gut microbiota. Antibiotic use has been connected with many serious health issues, such as increased risk for type-2 diabetes, obesity, cardiovascular disease and rheumatic arthritis. (2, 3, 4, 5)

Could garlic be a safer option for treating gut infections or a valuable addition to be used alongside conventional antibiotics?

Allicin – The antimicrobial substance of garlic

Garlic’s antimicrobial, antifungal and antiviral properties are most powerful if the garlic cloves are eaten raw and crushed.

Over 400 compounds have been found in garlic, with approximately 30 of those known to have health effects.

The sulfur-rich amino acid allicin is the most important antibiotic compound in garlic. When garlic is crushed or sliced, the enzyme alliinase becomes activated. Alliinase is responsible for converting sulfoxide alliin into allicin.

Allicin is a volatile compound and only survives for a few hours. The antibiotic properties of garlic are strongest 10 – 20 minutes after crushing or slicing the garlic cloves.

Besides the gut health benefits explored in this article, allicin is one of the only science-backed home remedies for curing a cold fast.

Garlic and bacterial infections

Researchers have found garlic to work antibiotically against multiple potentially pathogenic bacteria such as Helicobacter pylori, E.coli, Salmonella, Staphylococcus, Streptococcus, Klebsiella, Clostridium, Mycobacterium tuberculosis, and Bacillus. (6)

Garlic has also exhibited effectiveness against Campylobacter jejuni, which is a bacterium species commonly found in animal feces. C. jejuni is one of the most common causes of food poisoning and gastroenteritis in the world. (7, 8)

Bacteria, such as C. jejuni, can form biofilms around themselves to protect them from antibiotics and other medicine. According to an American study, diallyl disulfide, a compound in garlic, is 100 times more efficient in breaking C. jejuni biofilms than the antibiotics Ciprofloxacin and Erythromycin. (9)

Garlic for yeast infections and candida

Yeast colonies are normal residents in human bodies. Many different yeast species reside in our guts. However, the overgrowth of yeasts, such as Candida albicans could result in many health problems. A study conducted in the United Kingdom found that garlic’s constituent diallyl disulfide is an effective antifungal agent able to trigger cell death in Candida. (10)

Garlic’s antibiotic properties with parasites

Various studies have shown garlic to be also effective against parasites. Garlic has been observed to be able to combat Giardia, Entamoeba histolytica, and Trypanosomes. The anaerobic Giardia is the leading cause of diarrhea in the United States and worldwide. (11, 12, 13)

Colon cancer

Past observations have revealed that the short chained fatty acid butyrate decreases cancer cell numbers in those suffering from colon cancer. Butyrate is formed in the colon as beneficial bacterial species ferment soluble fibers. (14)

These fibers, which feed the good bacteria, are called prebiotics. 17% of garlic’s weight consists of inulin and oligofructose prebiotics, which are able to feed the good guys and promote butyrate production.

In a previous post, I wrote more extensively about using prebiotic foods and supplements to treat various health issues.

In addition to garlic promoting butyrate production by feeding the probiotics – the beneficial bacteria in our guts – research has also revealed that garlic’s diallyl disulfide is able to kill certain types of cancer cells. (15)

How to use garlic

Natural antibiotic

The reactions to eating raw garlic vary. Garlic may irritate the stomach and cause bloating or gas production as a result of the prebiotic fibers it contains. If you are taking medication, have been diagnosed with a disease, or are pregnant, you should consult your health-care professional on the safety of raw garlic before trying it.

1) In order to get garlic’s maximum antibiotic benefits you don’t want to cook it, as heat destroys most of the valuable allicin in garlic.

2) You have to eat the garlic clove 10 – 15 minutes after crushing or slicing it to maximize the allicin content.

3) To reduce stomach irritation, it is best to consume the garlic in a glass of water after eating food. This minimizes the gut irritation.

4) To avoid the garlic smell on your breath, place the sliced garlic at the bottom of a glass. Pour just a little water on it so that the garlic floats, and then stir it with a spoon if necessary, before swallowing the whole combination of garlic and water at once.

The way I take it, is that I first slice the clove, then put it in a glass, eat my food and drink the garlic-water down after eating.

Always start with just one clove of raw garlic to see how it feels. To treat bacterial infections, yeast overgrowth or SIBO, people have been taken 1 – 3 cloves of garlic per day for 1 – 5 days, for example. However, it is important be cautious and listen to your body.

One of the best uses of raw garlic is to treat acute food poisonings. Often just one or two cloves may stop diarrhea or other gut infections in their tracks.

Garlic supplements and other musings

Remember that garlic doesn’t suit everyone, nor does it work in every situation. Always see a doctor if you need to.

It is also important to note that many of the studies mentioned above were conducted in laboratory settings outside of human bodies. It is not clear whether garlic and its compounds have identical effects in our bodies.

Most of the garlic supplements available, such as Kyolic, are unlikely to have any antimicrobial effects because allicin gets broken down in a few days after the garlic is processed. However, there is at least one supplement, called Allimax, on the market in which the allicin is in a stabilized form.



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The writer or writers of this blog are not doctors. The content in this blog is not meant to treat or diagnose any disease. If you make any changes to your diet or lifestyle, you do so at your own risk. Consult your doctor before making any changes to your lifestyle.


  1. PL says:

    Interesting. For me, garlic seems to fend off colds and influenzas very effectively but slicing it small and waiting for 10 – 15 minutes before taking it was new for me.

  2. Rachel says:

    I have chopped the cloves to 3 or 4 pieces and swallowed them with juice. That always rids me of sinus infections. I’m gonna try the finely slicing next time I feel some illness threating me.

  3. Mark P says:

    I have used garlic for cold sores in my lips for a few years now. I either cut the clove in half and push the cut edge to the sore for a few minutes or I apply the paste of crushed garlic on top of the sore. This usually heals the sores within a day!

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