garlic (Allium sativum) is one of the most loved ingredients in kitchens worldwide. Beyond flavor, many people use garlic as part of traditional wellness routines. It contains natural sulfur compounds (like allicin) and provides small amounts of B vitamins and minerals.

But “natural” doesn’t always mean “risk-free.” For some people—especially in high amounts, on an empty stomach, or alongside certain medications—garlic can cause uncomfortable side effects.

⚠️ Educational content only. If you have a health condition, take medication, or are preparing for surgery, check with a qualified professional before using large amounts of garlic or garlic supplements.

Quick Nutrition Snapshot (Raw garlic)

Raw garlic is low in water and dense in plant compounds. It also contains carbohydrates, small amounts of protein, and trace vitamins/minerals (especially B vitamins and minerals like manganese and potassium).

15 Side Effects of garlic (What to Watch For)

1) Bad Breath and Body Odor

This is the most common complaint. garlic’s sulfur compounds can affect breath and sweat.

2) Heartburn and Acid Reflux

Raw garlic—especially on an empty stomach—may irritate the digestive tract and trigger reflux in sensitive people.

3) Nausea or Stomach Upset

Some people feel queasy after raw garlic, particularly in large amounts.

4) Gas, Bloating, or Abdominal Discomfort

garlic contains fructans (a type of carbohydrate) that can cause bloating, especially in people with IBS or sensitive digestion.

5) Diarrhea

Too much raw garlic may speed up digestion and lead to loose stools.

6) Irritation of Ulcers or Gastritis

If you already have stomach inflammation or ulcers, garlic may worsen discomfort.

7) Low Blood Pressure (Feeling Light-Headed)

garlic may support lower blood pressure, which can be an issue if you already run low—or if you’re taking blood pressure medication.

8) Dizziness or Fatigue

For some people, a drop in blood pressure can feel like dizziness, weakness, or brain fog.

9) Increased Sweating

A few people report sweating more after high garlic intake.

10) Higher Bleeding Risk (Important)

garlic can have a mild blood-thinning effect. This matters most if you:

Take anticoagulants/antiplatelets
Have a bleeding disorder
Have surgery scheduled (many clinicians advise stopping supplements ahead of procedures)

11) Drug Interactions

garlic (especially supplements) may interact with certain medications, including blood thinners and some antiviral or metabolic medications. Always check if you’re on long-term prescriptions.

12) Skin Irritation or Rash (Contact)

Handling raw garlic or applying it to skin can cause redness, itching, or dermatitis in sensitive people.

13) Burns or Blisters from Topical garlic

Applying raw garlic directly to skin (or leaving it on too long) can cause chemical irritation or burns.

14) Headache Triggers in Sensitive People

Strong smells and certain food compounds can trigger headaches for some individuals. If garlic consistently triggers migraines, consider reducing it.

15) “DIY” garlic Use in Sensitive Areas (Avoid)

Using garlic in delicate areas (for example, inserting it internally) can irritate tissue and make symptoms worse. It’s not a safe home practice.

How Much garlic Is “Reasonable”?

Many people tolerate 1–2 raw cloves per day (or cooked garlic in meals) without problems, but tolerance varies a lot.

Gentler options if you’re sensitive:

Use cooked garlic instead of raw
Start with small amounts
Eat it with food, not on an empty stomach
Take breaks instead of daily high doses

Who Should Be Extra Careful?

Be cautious with high-dose garlic or supplements if you:

Take blood thinners
Have surgery planned
Have ulcers, gastritis, or IBS symptoms
Have low blood pressure
Are pregnant/breastfeeding (ask a professional first)

Final Thoughts

garlic can be a wonderful part of healthy eating—but more is not always better. If you notice discomfort, reduce the dose, choose cooked garlic, and prioritize a balanced diet.

15 Unwanted Side Effects of Garlic You Should Know