Garlic is one of the world’s most popular culinary ingredients. Its strong aroma and distinctive flavor can transform everything from soups and sauces to roasted vegetables, meat, and rice.

Beyond cooking, garlic has also attracted considerable interest because it contains sulfur-containing compounds and other substances that have been studied for potential health effects.

For most people, garlic is safe when consumed in normal food amounts. However, eating very large quantities of raw garlic or taking concentrated garlic supplements can cause unwanted effects.

The important point is that garlic is not automatically harmful simply because it has side effects. As with many foods and supplements, the amount, form, frequency of use, and a person’s individual health conditions all matter.

Here are 15 possible side effects and precautions worth knowing.

1. Bad Breath

The most familiar side effect of eating garlic is also one of the hardest to hide.

Garlic contains sulfur-containing compounds that contribute to its characteristic smell. Some of these compounds can remain in the mouth and may also be released through the lungs after digestion.

Brushing your teeth can help, but the odor may persist for several hours.

2. Strong Body Odor

Garlic can sometimes affect more than your breath.

Certain sulfur compounds can be excreted through sweat and other bodily fluids, potentially giving the skin a noticeable garlic-like odor.

This is generally harmless but can become more noticeable after consuming large quantities.

3. Heartburn

Raw garlic can cause burning or discomfort in the upper digestive tract in some people.

Individuals who already experience acid reflux or heartburn may find that large amounts of garlic—particularly raw garlic—make their symptoms worse.

If garlic repeatedly triggers burning after meals, reducing the amount or choosing cooked garlic may help.

4. Stomach Upset

Eating a lot of garlic can irritate the digestive system.

Possible symptoms include:

• Stomach discomfort
• Bloating
• Nausea
• Abdominal pain
• A feeling of fullness

These effects are more likely when someone suddenly consumes a large quantity, especially on an empty stomach.

5. Gas and Bloating

Garlic contains carbohydrates that can be difficult for some people to digest.

For individuals with sensitive digestive systems or irritable bowel syndrome (IBS), garlic may contribute to fermentation in the gut, resulting in:

• Gas
• Bloating
• Abdominal discomfort

People who follow a low-FODMAP diet are often advised to limit garlic because it is high in fructans.

6. Diarrhea

Large quantities of garlic, particularly raw garlic or concentrated preparations, may cause loose stools or diarrhea in sensitive individuals.

If diarrhea occurs after increasing garlic intake, reducing the amount and monitoring symptoms can help determine whether garlic is contributing to the problem.

Persistent diarrhea should not automatically be blamed on garlic and may require medical evaluation.

7. Nausea

Some people experience nausea after eating substantial amounts of raw garlic.

The intense flavor and compounds released from crushed garlic may be particularly unpleasant for sensitive stomachs.

Cooking garlic can make it easier for some people to tolerate.

8. Mouth or Throat Irritation

Raw garlic is much more intense than cooked garlic.

Chewing large amounts of raw garlic can cause burning or irritation of the mouth, tongue, throat, or digestive tract.

Applying raw garlic directly to the skin or inside the mouth is also not recommended because concentrated garlic can cause irritation and even burns.

9. Increased Bleeding Risk

This is one of the more important precautions involving concentrated garlic supplements.

Garlic may have antiplatelet effects, meaning it can affect how platelets participate in blood clotting.

This can be particularly important for people taking medicines that also affect bleeding, such as:

• Warfarin
• Apixaban
• Rivaroxaban
• Clopidogrel
• Aspirin

The risk depends on the person’s medication, dose, health conditions, and amount of garlic consumed.

Normal culinary use is generally very different from taking concentrated garlic supplements.

If you take blood-thinning or antiplatelet medication, talk with your healthcare professional before starting a garlic supplement.

10. Possible Interaction With Certain Medicines

Garlic supplements can interact with some medications.

The concern is generally greater with concentrated supplements than with the small amounts normally used in cooking.

Because supplements can vary substantially in strength, anyone taking several prescription medications should discuss regular garlic supplementation with a doctor or pharmacist.

Do not stop a prescribed medication simply because you have started eating garlic.

11. Low Blood Pressure in Some People

Garlic has been studied for its potential blood-pressure-lowering effects.

For people with hypertension, this may sound beneficial. But someone who already has low blood pressure or takes several blood-pressure-lowering medications may need to be more cautious with concentrated garlic supplements.

Possible symptoms of excessively low blood pressure include:

• Dizziness
• Lightheadedness
• Weakness
• Fainting

If these symptoms occur, medical advice may be necessary.

12. Allergic Reactions

Although uncommon, garlic allergy is possible.

Symptoms can include:

• Itching
• Skin rash
• Hives
• Swelling
• Breathing difficulties

A severe allergic reaction can be an emergency.

Anyone who develops difficulty breathing, swelling of the lips or throat, or severe dizziness after eating garlic should seek emergency medical attention.

13. Skin Irritation and Burns From Raw Garlic

Eating garlic is very different from putting raw garlic directly on your skin.

Concentrated raw garlic can cause significant skin irritation and chemical-like burns, particularly when it is left against the skin for an extended period.

This is especially important because garlic is sometimes promoted online as a home remedy for infections, acne, warts, or other skin problems.

Applying raw garlic to damaged or sensitive skin is not a safe substitute for appropriate medical treatment.

14. Headache or General Discomfort in Sensitive Individuals

Some people report headaches or general discomfort after consuming particular foods, including garlic.

This does not mean garlic commonly causes headaches. Rather, individual food sensitivities vary considerably.

If headaches consistently occur shortly after consuming large amounts of garlic, keeping a food diary may help identify patterns.

However, repeated or severe headaches should be evaluated rather than automatically attributed to garlic.

15. Digestive Problems in People With IBS or Food Sensitivities

Garlic can be particularly troublesome for people with certain digestive conditions.

Its fructan content can trigger symptoms in some individuals with IBS or sensitivity to fermentable carbohydrates.

Symptoms may include:

• Bloating
• Gas
• Abdominal pain
• Changes in bowel movements

This doesn’t mean everyone with IBS must permanently avoid garlic.

Some people can tolerate small quantities, garlic-infused oil, or other preparations better than whole garlic because the fructans are not soluble in oil.

A dietitian can help determine individual tolerance when symptoms are persistent.

Who Should Be Especially Careful With Garlic Supplements?

Garlic used as a normal ingredient in food is generally well tolerated.

More caution is appropriate when using garlic capsules, extracts, powders, oils, or other concentrated supplements.

Speak with a healthcare professional before using concentrated garlic supplements if you:

• Take anticoagulant or antiplatelet medication
• Have a bleeding disorder
• Have very low blood pressure
• Take several medications
• Have an upcoming surgery
• Are pregnant or breastfeeding
• Have significant digestive problems
• Have previously experienced an allergic reaction to garlic

Your doctor or pharmacist can consider your complete medication list and medical history.

Raw Garlic vs. Cooked Garlic

Not all garlic is consumed in the same way.

Raw garlic generally has a stronger flavor and may cause more digestive or mouth irritation than cooked garlic.

Cooking changes garlic’s chemical composition and can reduce some of its pungency.

That doesn’t mean cooked garlic has no nutritional value. Garlic can still be a flavorful way to add variety to meals while reducing the need for excessive salt or heavily processed sauces.

How Much Garlic Is Too Much?

There is no single amount that causes side effects in everyone.

Tolerance varies according to:

• Individual digestion
• Overall diet
• Whether garlic is raw or cooked
• Amount consumed
• Use of supplements
• Existing health conditions
• Medications

A small amount used to season food is very different from eating several raw cloves every day or taking a concentrated garlic extract.

If garlic consistently causes symptoms, the answer isn’t necessarily to eliminate it forever. Reducing the quantity or changing how it is prepared may be enough.

Is Garlic Still Healthy?

Absolutely—for many people, garlic can be part of a healthy diet.

Garlic provides flavor without requiring large amounts of salt, sugar, or highly processed sauces.

Research has also investigated garlic and garlic preparations for possible effects on blood pressure, cholesterol, cardiovascular risk factors, and other areas of health.

However, these potential benefits should not be interpreted as proof that garlic can prevent or cure every disease.

A healthy diet is built around the overall pattern of foods you eat—not one “superfood.”

How to Enjoy Garlic More Comfortably

If garlic tends to bother your stomach, consider these approaches:

Use Smaller Amounts

Instead of several cloves, start with a modest quantity and see how your body responds.

Cook It

Cooked garlic is often milder and may be easier to tolerate than raw garlic.

Eat It With a Meal

If raw garlic causes stomach irritation, consuming garlic as part of a balanced meal may be more comfortable than eating it by itself.

Avoid Concentrated Supplements Unless Needed

Food and supplements are not equivalent.

A garlic supplement can deliver a much more concentrated amount of active compounds than ordinary culinary use.

Pay Attention to Your Own Symptoms

If you consistently experience bloating, heartburn, diarrhea, or another symptom after eating garlic, don’t ignore the pattern.

Reducing your intake and discussing persistent symptoms with a healthcare professional can be more useful than following a generic recommendation online.

When Should You Seek Medical Help?

Most garlic-related side effects are mild and disappear after reducing intake.

However, seek medical attention for symptoms such as:

• Difficulty breathing
• Swelling of the face, lips, tongue, or throat
• Severe or persistent abdominal pain
• Unexplained bleeding
• Black or bloody stools
• Vomiting blood
• Fainting
• Persistent severe diarrhea

These symptoms may have causes unrelated to garlic and should not simply be dismissed as a food reaction.

The Bottom Line

Garlic can be a nutritious and flavorful part of a balanced diet, but more is not always better.

For most people, the amounts used in everyday cooking are unlikely to cause serious problems. The likelihood of side effects can increase when someone consumes large amounts of raw garlic or uses concentrated garlic supplements.

The most common issues include bad breath, body odor, heartburn, gas, bloating, nausea, stomach discomfort, and diarrhea. More important precautions involve potential effects on bleeding, blood pressure, medication interactions, and skin irritation from applying raw garlic directly to the skin.

If you take prescription medication—especially blood-thinning, antiplatelet, or blood-pressure medication—talk with a healthcare professional before using concentrated garlic supplements.

Garlic doesn’t need to be feared, and it doesn’t need to be treated as a miracle cure either. Used sensibly as part of a varied diet, it can remain a flavorful and useful ingredient without overdoing it.

Frequently Asked Questions

Is eating garlic every day safe?

For most healthy adults, moderate amounts of garlic used in food are generally well tolerated. Problems are more likely with large quantities, raw garlic, or concentrated supplements.

Can garlic cause stomach problems?

Yes. Garlic can cause heartburn, gas, bloating, nausea, abdominal discomfort, or diarrhea in some people, particularly when consumed in large amounts.

Can garlic thin the blood?

Garlic may have antiplatelet effects, particularly in concentrated supplement forms. People taking anticoagulants or antiplatelet medicines should discuss garlic supplements with their healthcare professional.

Can raw garlic burn the skin?

Yes. Concentrated raw garlic can cause significant skin irritation and burns. It should not be used as a homemade treatment by placing raw garlic directly on the skin.

Is cooked garlic safer than raw garlic?

Cooked garlic is generally less pungent and may be easier for some people to tolerate. However, individual responses vary.

Can garlic lower blood pressure?

Garlic preparations have been studied for possible blood-pressure-lowering effects. However, garlic should not replace prescribed blood-pressure treatment, and people taking blood-pressure medication should be cautious with concentrated supplements.

Who should avoid garlic supplements?

People taking blood-thinning or antiplatelet medicines, those with bleeding problems, people preparing for surgery, and individuals taking multiple medications should consult a healthcare professional before using concentrated garlic supplements.

SEO Details

SEO Title: 15 Possible Side Effects of Garlic You Should Know About

Meta Description: Garlic is healthy for many people, but too much can cause side effects. Learn about 15 possible garlic side effects, medication interactions, and safety tips.

Focus Keyword: side effects of garlic

Secondary Keywords: garlic side effects, disadvantages of eating garlic, raw garlic side effects, garlic supplements, garlic and blood thinners, garlic digestive problems