Garlic (Allium sativum L.) is a plant widely valued both for its powerful medicinal properties and for its distinctive flavor in cooking. For thousands of years, raw garlic has been used in traditional medicine across many cultures. Modern scientific research now confirms that garlic offers a wide range of health benefits, including strengthening the immune system, supporting cardiovascular health, reducing inflammation, and helping the body fight infections such as colds and flu.

One of garlic’s most remarkable features is its strong antibacterial activity. A study published in the Journal of Antimicrobial Chemotherapy found that a garlic compound called diallyl disulfide was up to 100 times more effective than two commonly used antibiotics in killing Campylobacter bacteria. Even more impressive, this compound destroyed the bacteria in a much shorter time than the antibiotics. (35)

Garlic can be used medicinally by chopping or crushing fresh cloves and consuming them raw. For those who dislike the strong taste or experience digestive discomfort, garlic supplements and capsules are popular alternatives. Regardless of how garlic is consumed, consistent intake has been shown to support overall health and wellness.

In this article, we will explore what scientific research reveals about using garlic as a natural medicine. You will learn how raw and dried garlic can boost immunity, support vital organs, and help protect against infections and chronic disease.

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Nutritional Value of Garlic

Garlic belongs to the Allium family, which also includes onions, leeks, shallots, and chives. Each garlic bulb (or head) contains around 10–12 individual cloves.

Mincing one small clove produces approximately ½ teaspoon, while a large clove yields about 1½ teaspoons.

Despite its small size, garlic is exceptionally nutrient-dense and very low in calories. Just three garlic cloves provide the following nutrients: (1)

• 8 mg vitamin C (5% RDI)

• 0.1 mg vitamin B6 (6% RDI)

• 16 mg calcium

• 36 mg potassium

• 13 mg phosphorus

• 8 mg omega-3 fatty acids

• 3 g carbohydrates

• 13 calories

Garlic also contains small amounts of vitamins A and K, along with several B vitamins, making it a valuable addition to a balanced diet.

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Medicinal Compounds in Garlic

The health-promoting effects of garlic come largely from its sulfur-containing compounds, which act as antioxidants in the body.

The most important medicinal compound in garlic is allicin. According to a review on garlic’s therapeutic properties, allicin is the primary bioactive compound in raw garlic. It has antimicrobial, anticancer, and blood-pressure-lowering effects. Allicin is released only when garlic is chopped, crushed, or chewed. (2)

Garlic also contains phenolic compounds, flavonoids, and other antioxidants that protect cells from oxidative stress. (3) Additionally, garlic provides omega-3 and omega-6 fatty acids, which play an important role in brain function and nervous system health. (4)

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Proven Health Benefits of Garlic (Raw and Dry)

Garlic Boosts the Immune System

Eating raw garlic can significantly strengthen immune function. While many people use aged garlic extract supplements, studies show that fresh garlic is also highly effective.

In one study, 17 volunteers consumed a meal containing 5 g of crushed raw garlic (about two cloves). Blood tests taken three hours later showed enhanced immune activity. (8)

Other studies found that garlic stimulates the production of T-cells, which are essential white blood cells involved in immune defense. (9, 10) Garlic’s antibacterial properties may also increase the effectiveness of certain antibiotics. (11)

Raw garlic provides the most allicin, but high-quality supplements can be a good alternative for those sensitive to its taste or smell.

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Garlic Helps Fight Colds and Flu

Garlic consumption has been linked to reduced frequency and severity of cold and flu infections.

A 2016 study found that adults who took aged garlic extract daily during flu season experienced fewer and milder symptoms. (5) Another trial showed that people taking allicin-containing garlic supplements were less likely to catch a cold, and when they did, recovery was faster. (6)

Garlic enhances immune cell activity, helping the body fight viral infections more effectively. (7)

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Garlic Supports Heart Health

Garlic is widely recognized for its cardiovascular benefits. Reviews of multiple studies have concluded that garlic helps prevent heart disease and may also assist in managing existing cardiovascular conditions. (12, 13)

Garlic improves blood vessel function, reduces oxidative stress, and helps maintain healthy circulation.

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Garlic Helps Lower Blood Pressure

Garlic helps protect the heart by reducing high blood pressure. A review of 20 clinical trials involving more than 970 participants found that garlic supplements significantly lowered both systolic and diastolic blood pressure—sometimes by as much as 8.7 mm Hg. (14)

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Garlic Lowers Cholesterol Levels

Sulfur compounds in garlic help reduce cholesterol, particularly LDL (“bad”) cholesterol.

A 2018 review of 14 studies found that garlic supplementation consistently reduced total cholesterol and LDL cholesterol. (15) Combining fresh garlic with lemon juice has also been shown to improve cholesterol profiles. (16)

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Garlic Helps Regulate Blood Sugar

Garlic supplementation has demonstrated benefits for people with type 2 diabetes.

Studies show that consuming up to 1.5 g of garlic daily can reduce fasting blood glucose within one to two weeks. (17) Both dry garlic powder and allicin-enhanced supplements have proven effective. (34)

Animal studies further indicate that aged garlic extract is just as effective as fresh garlic in controlling blood sugar. (18)

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Garlic Reduces Inflammation

Chronic inflammation contributes to many diseases. Studies show that aged garlic extract significantly reduces inflammatory markers.

In one study, adults who took 3.6 g of garlic extract daily for six weeks showed reduced inflammation, suggesting garlic may help prevent chronic disease. (19)

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Garlic Fights Fungal and Bacterial Infections

Allicin in garlic has strong antifungal activity. Laboratory studies show it effectively kills Candida albicans. (20) Human studies confirm that garlic supplements reduce fungal infections while also lowering inflammation. (21)

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Garlic Protects Liver Health

Garlic’s antioxidants help protect the liver from damage.

In people with nonalcoholic fatty liver disease, garlic powder supplementation reduced body weight and improved liver markers. (22) Other studies show benefits for alcohol-related liver damage. (23)

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Garlic Supports Brain Health

Garlic extracts may protect against cognitive decline. Animal studies show that aged garlic extract reduces brain inflammation, improves memory, and protects against oxidative stress and stroke-related damage. (24, 25)

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Garlic Treats Gastric Ulcers

Garlic’s antibacterial effects help fight Helicobacter pylori, the bacteria responsible for most gastric ulcers.

Clinical studies found that consuming raw garlic significantly reduced H. pylori levels and improved ulcer symptoms. (26, 27)

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Garlic Strengthens Bones in Menopausal Women

Garlic supplementation may help reduce osteoporosis risk in menopausal women. Studies show improved antioxidant levels and reduced bone breakdown after regular garlic intake. (28)

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Garlic Has Anticancer Properties

Numerous studies link garlic consumption to reduced risk of cancers such as stomach, colorectal, breast, pancreatic, and esophageal cancer.

The National Cancer Institute reports strong evidence that both raw and cooked garlic have cancer-protective effects, likely due to antibacterial action, reduced cell proliferation, and improved DNA repair. (29)

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Garlic Supplements vs. Raw Garlic

Raw garlic provides the most allicin, which forms only when garlic is crushed or chopped. (30) While some studies suggest fresh garlic is more potent, supplements such as aged garlic extract still offer significant health benefits. (31, 32)

Supplements are often preferred due to fewer side effects like bad breath and digestive irritation.

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Recommended Garlic Intake

There is no official daily dose, but the World Health Organization suggests 1–2 cloves per day for health benefits. Many people safely consume 3–4 cloves daily, and some studies used up to six cloves with positive effects. (16, 29)

To preserve allicin:

• Crush garlic and let it sit for 10 minutes before cooking

• Cook on low or medium heat

• Avoid microwaving garlic

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How to Use Garlic Daily

• Crush 2–3 cloves and let them sit before eating

• Mix with yogurt or honey to reduce strong flavor

• Use fresh garlic whenever possible

• Consider growing garlic at home

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Side Effects and Precautions

Garlic is generally safe, but may cause:

• Bad breath and body odor

• Digestive upset when eaten on an empty stomach

• Gas, nausea, or diarrhea (33)

Garlic should never be applied raw directly to the skin, as it can cause burns.

If you take medication for blood pressure, diabetes, or blood clotting, consult your doctor before using garlic supplements. Garlic may enhance the effects of these medications. (30)