15 Serious Side Effects Of Garlic (Foods To Avoid With It)

Garlic has a strong, pungent taste and is flavorful. This herb has medicinal properties. But, did you ever give a thought to the side effects of garlic?

Excess intake of garlic (Allium sativum) has been linked with bleeding disorders, diarrhea, liver damage, vomiting, nausea, and heartburn.

So, is garlic bad for you? This article explores the 14 adverse effects of garlic and things to consider before consuming it. Let’s get started.

Know The Flip Side: Garlic

Short-Term Effects
It can cause bad breath, vomiting, nausea, heartburn, diarrhea, sweating, lower blood sugar levels.

Long-Term Effects
May aggravate bleeding issues and lead to liver damage, eczema, and even vision issues.

Drug Interactions
Interacts with blood-thinners and raises the risk of bleeding out.

When To See A Doctor
If you experience excessive stomach discomfort, very low blood sugar levels and nose bleeds, seek medical help.

What Are The Side Effects Of Garlic?

1. May Cause Liver Damage

Excess garlic consumption may affect the liver. Though raw garlic has antioxidant potential, excess intake can lead to liver toxicity (1). As per rat studies, garlic in high doses (0.5 grams per kg of body weight) may induce liver damage. However, low doses of garlic (0.1 grams to 0.25 grams per kg of body weight) on a daily basis are safe for the liver (2).

2. May Cause Bad Odor

As per one Italian report, garlic breath and body odor were two of the most common adverse effects associated with garlic (3). Lack of personal hygiene is not the only cause of body odor, as consumption of garlic may result in it too (4).

Youtuber Thando shared her experience with eating raw garlic for 7 days in a video. She said, “After eating it, obviously your mouth’s going to smell garlicky, but after that, you can shower and then brush your teeth (i).” She noted another downside saying that garlic goes down slowly and burns in the mouth and esophagus.

Garlic odor has been found to linger in the mouth long after brushing. Certain experts believe that the chemicals in garlic that contribute to bad breath odor are the same chemicals that also render it its benefits (5). However, bad breath can be embarrassing. Hence, you probably need to think twice before consuming garlic. You may also take precautions and use a mouth-refreshing spray.

Quick Tip

Consuming milk alongside eating garlic may help reduce the malodor. Having mushrooms, basil, or water with garlic may also help (24).

3. May Cause Nausea, Vomiting, And Heartburn

Anecdotal evidence suggests that consuming fresh garlic bulbs on an empty stomach may cause acid reflux, nausea, vomiting, and heartburn. Certain observational studies have also stated that taking garlic orally can cause heartburn and nausea (6). Excess garlic intake may also cause GERD (gastroesophageal reflux disease) in some individuals. More research is needed to understand this side effect of garlic.

4. May Cause Diarrhea

Consuming fresh garlic in excess can cause diarrhea. Garlic may trigger diarrhea as it may cause gas (7).

5. May Cause Gastric Issues

One Japanese study speaks about enteric-coated garlic products (products coated with a polymer barrier to prevent disintegration in the gastric environment). These garlic products, upon ingestion, resulted in the reddening of the gastric mucous membrane and can cause gastrointestinal discomfort (8). The results suggest that caution must be exercised before using garlic and related products as they may have undesirable effects on gastric health.

In fact, as against popular belief, there is no evidence that links garlic intake to the prevention of gastric cancer (9).

6. May Lower Blood Pressure Way Too Much

Garlic may lower blood pressure (10). But if you are already on medications for high blood pressure, it may lead to hypotension (low blood pressure). Supplemental garlic has also shown to lower blood pressure levels (11). Hence, taking garlic supplements could be a bad idea when you are already on blood pressure medications. Taking garlic by mouth can also modestly reduce blood pressure (12).

In a meta-analysis of 553 hypertensive participants and 12 trials, garlic supplements were proven to lower systolic blood pressure by an average of 8.3±1.9 mmHg and diastolic blood pressure by 5.5±1.9 mmHg.

7. May Aggravate Bleeding

Garlic may increase the risk of bleeding. Hence, it must not be taken along with blood-thinning medications like warfarin (13).

This is true especially in the case of fresh garlic. It also is better to stop garlic consumption at least 7 days before a scheduled surgery. Garlic has antiplatelet effects and may cause increased bleeding tendency during surgery (14).

8. May Induce Sweating

As per some studies, garlic may also cause profuse sweating in certain individuals (15). However, we need more research in this regard.

9. May Cause Dizziness

Excess garlic intake can cause dizziness, fatigue, and fainting (16). The mechanism behind this action is yet to be studied.

10. May Cause Eczema Or Rashes

Prolonged contact with garlic may cause skin irritation. Some specific enzymes in garlic may lead to this irritation. As per anecdotal evidence, eczemaⁱ  XA skin condition most commonly diagnosed in young children that causes redness, dryness, itchiness, and inflammation. could also be one of the conditions that accompany this allergy.

Quick Tip

If you are allergic to garlic, you may also be allergic to onions, shallots, chives, and leeks as they belong to the same botanical family and have the same proteins.

11. May Interact With Certain Drugs

As per one study, garlic was found to interact with medications, such as chlorpropamide, fluindione, ritonavir, and warfarin (18).

12. May Cause Headache

Garlic, especially when taken in its raw form, could trigger migraines (19). Though it doesn’t directly cause a migraine headache, it activates the process responsible for it.

Though the exact reason for this is unclear, certain experts believe it may involve the trigeminal nerve – the major pain pathway in the body. Taking garlic may stimulate this nerve to release neuronal signaling molecules called neuropeptides that rush to the membrane covering your brain and cause headaches.

13. May Aggravate (Vaginal) Yeast Infection

Garlic cloves may irritate the tender tissue of the vagina (20). Certain women insert garlic cloves into the vaginas as a remedy to treat vaginal yeast infections. This is not recommended.

14. May Cause Vision Changes

It has been found that excessive ingestion of garlic can lead to a condition called hyphema, which refers to bleeding inside the eye chamber – the space between the iris and the cornea (16). Taking large doses of garlic, an anticoagulantⁱ  XA group of medicines that reduce the formation of blood clots and prolong the clotting time. Also known as blood thinners. , may cause or aggravate hyphema. Hyphema may also cause permanent vision loss.

Anecdotal evidence suggests certain other side effects of garlic too. Excess intake may cause loss of appetite. Garlic overdose may lead to kidney hematomas (swelling of clotted blood within the tissues of kidneys), chemical burns in the mouth, and life-threatening allergic reactions. It can even cause difficulty breathing and wheezing and even trigger anaphylaxis.

Garlic may also cause a condition called pemphigus, an autoimmuneⁱ  XA condition in which the immune system cannot differentiate between healthy cells and foreign cells and attacks its own body cells. disease (21).

15. May Cause Blistering

Dermal contact with garlic may cause blistering in people who are allergic to it (22). This condition is also known as garlic burn and is attributed to the presence of compounds like allicin, which may cause skin irritation and induce allergic reactions (23).

The degree of burn depends on factors like the sensitivity of the skin and duration of exposure. Handling garlic or garlic juice for an extended period of time may cause burning, redness, and itching and may even lead to necrosis. Furthermore, crushed raw garlic is a potent irritant that may cause irritant contact dermatitis, a condition characterized by itchy rashes, in previously sensitized individuals (22). Hence, practice caution while handling garlic.

There is a list of foods that may cause side effects if taken along with garlic. We have covered those in the following section.

What Should You Avoid While Taking Garlic?

It is best you avoid consuming certain foods with garlic to keep the side effects at bay. These include:

• Clove
• Ginger
• Ginkgo
• Horse chestnut
• Red clover
• Turmeric
• Willow
• Capsicum
• Poplar
• Danshen

The intake of too much garlic can cause adverse effects. But, how much garlic is too much? Scroll down to learn recommended dosage of garlic.

Dosage

Jesse Feder, a Clinical Dietitian with the Memorial Regional Hospital South, says, “Garlic is not toxic. However, it is typically recommended to only have 1-2 raw garlic cloves in a day.”

Infographic: Ingredient Spotlight: Garlic

Garlic is widely used in culinary delights and traditional home remedies. There is, however, a downside to every coin, and excessive garlic consumption can be detrimental to health.

Check out the infographic below to learn more about garlic, its recommended daily dietary intake, and some alternatives for this pungent condiment. Scroll down.

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Frequently Asked Questions

How long does garlic stay in your system?

Jesse Feder says, “Certain sulfur compounds in garlic may take up to two days to get out of your system.” Garlic will stay in your system for 24 to 48 hours. Spices like garlic get excreted through your sweat as well as your digestive system.

Is garlic stronger than antibiotics?

According to Jesse, “Garlic is not stronger than antibiotics, even though garlic has some antibiotic properties.”

Does garlic affect urine?

Jesse agrees and says, “Garlic contains certain compounds that can affect the smell of your urine.”

Can I drink water after eating garlic on an empty stomach?

Jesse says, “You can and should drink water after eating garlic on an empty stomach. This can help prevent some indigestion and gas.”

Why does my stomach hurt when I eat garlic?

Garlic is high in fructans. Anecdotal evidence suggests that it may cause difficulty in digestion in some individuals. It may lead to upset stomach, abdominal pain, bloating, flatulence, and gas in some people.

Does garlic elevate blood pressure levels?

There is no research to support that garlic can elevate blood pressure levels.

Does garlic induce labor in pregnant women?

There is no research to state the same. However, pregnant women can consult their doctor before taking garlic.

What is the healthiest way to eat garlic?

The healthiest way to eat garlic is in its raw form. That way, you can get the maximum benefit of allicin, the compound in garlic responsible for its beneficial effects.

Does garlic make you pee a lot?

No studies suggest that garlic increases the frequency of peeing or the volume of urine. However, anecdotal evidence suggests that spicy foods like onion, garlic, and ginger may make you pee more.

Don’t make the same mistake many people do when taking garlic! Watch this video to learn how best to ingest your garlic and do it correctly!

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Alexandra DusenberryMS, RDN

   

Alexandra Dusenberry is a registered dietitian nutritionist and a certified personal trainer based in San Diego, California. She has 6 years of experience and works with clients around the world to help them reach their health and fitness goals. She believes that food is medicine and proper nutrition is healing and essential for wellbeing and quality of life. Alexandra enjoys...more

• Jesse FederRDN/LDN

  Jesse Feder, RDN/LDN, is a Clinical Dietitian at the Memorial Regional Hospital. He is also a certified by the American College of Sports Medicine as a personal trainer (ACSM-CPT) and the National Strength and Conditioning Association as a Certified Strength and Conditioning Specialist (NSCA-CSCS).
  
  Jesse Feder, RDN/LDN, is a Clinical Dietitian at the Memorial Regional Hospital. He is also a certified by the American College of Sports Medicine as a personal trainer (ACSM-CPT) and the National Strength and Conditioning Association as a Certified Strength and Conditioning Specialist (NSCA-CSCS).

Ravi Teja TadimallaSenior Editor

 

Ravi Teja Tadimalla is a senior editor and a published author. He has been in the digital media field for over eight years. He graduated from SRM University, Chennai, and has a Professional Certificate in Food, Nutrition & Research from Wageningen University. He has written over 300 articles about ingredients and their benefits for the skin, hair, and health. He...more

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Arshiya Syeda is a senior editor at StyleCraze with 7 years of experience. Prior to that, she was a content writer and combined her writing and research skills to write over 200 high-performing articles on hairstyles, hair care, and skin care. She holds a bachelor's degree in literature and psychology from Osmania University, Hyderabad, and a post-graduate diploma in psychological...more

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Sindhu Koganti is a Certified Health and Nutrition Life Coach and has over 6 years of experience in writing on health and wellness topics. She has a bachelor’s degree in biotechnology from Acharya Nagarjuna University, Guntur, and a diploma in nutrition from Fab Academy. After her graduation, she decided to combine her knowledge of science and love for writing to...more