We asked a dietitian and healthcare expert to break down the science behind garlic’s potential immune-boosting powers and whether it can actually help you beat a bad cold.

What the research says about garlic for colds

Garlic isn’t just for spicing up your pasta—it’s been used as food and medicine for thousands of years, dating back to ancient Egypt. The magic lies in allicin¹, a compound with powerful antimicrobial and antioxidant properties that support immune health, says dietitian Bonnie Taub-Dix, RDN, a registered dietitian nutritionist, author of Read It Before You Eat It - Taking You from Label to Table, and host of the Media Savvy Podcast. But can garlic really help you kick a cold?

Some promising evidence suggests that it can: One study in particular found that participants who took a garlic supplement (180 milligrams of allicin daily for 12 weeks) had significantly fewer colds²—24 occurrences compared to 65 in the placebo group. While that is a big difference, the authors cautioned that more research is needed to back up the findings.

A slightly newer systematic review—published in 2020 in Trends in Food and Science Technology—also found that garlic and its organosulfur compounds (ingredients containing the mineral sulfur, which can be found in other veggies like leeks, broccoli, and onions) have antiviral properties³ that may help prevent viral infections.

While these studies point to garlic’s potential, experts agree that more high-quality research is needed to confirm its effectiveness in preventing or treating colds. That said, it's still worth giving it a try (if you're not allergic, of course) to see if it helps you personally.

4 potential benefits of raw garlic

Raw garlic isn’t just a kitchen staple—it’s a little powerhouse of health perks. Here are a few potential health benefits you can reap from eating the aromatic vegetable.

1. It may boost immune health

The saying goes "an apple a day keeps the doctor away," but a clove of garlic might also have some immune-boosting benefits that rival the popular fruit. Case in point: garlic is thought to stimulate immune cells like macrophages and T- and B-cells, which help fight infection and produce antibodies, says William Li, MD, physician-scientist and author of Eat to Beat Disease. Studies have even found that aged garlic extract⁴ is associated with enhanced immune cell function because it helps immune cells replicate faster.

2. It may help prevent colds

Apart from helping fight off infection, some research suggests that garlic's bioactive ingredient allicin also contains antiviral properties⁵ that might help prevent viruses like the common cold, says Dr. Li. The same 2020 review in Trends in Food and Science Technology mentioned earlier backs this up, highlighting garlic’s potential in preventing colds and other viral infections by blocking pathogenic viruses⁶ from entering into host cells.

3. It may help support your heart

Apart from immune system support, garlic is also considered a heart-healthy ingredient. According to Dr. Li, eating garlic almost every day may:

• Lower blood pressure⁷, a major risk factor for heart disease.
• Prevent cholesterol plaque buildup⁸ in arteries (which can often lead to a condition called atherosclerosis).
• Improve the lining of your blood vessels, which is crucial for cardiovascular health.

That said, not all studies agree on these benefits. While older studies found that garlic lowers cholesterol, newer research hasn't resulted in the same effect. This is important to keep in mind when treating an underlying heart condition; guidance from your healthcare provider and proper medication should remain the first line of care.

4. It may be protective against certain cancers

Research is limited, but some early evidence suggests that garlic (and other allium vegetables like onion) may have some cancer-fighting qualities—mostly due to its positive influence on immune cells. One review found that people who increased their garlic intake had a lower risk of certain gastrointestinal cancers⁹ such as stomach, colorectal, and esophageal cancer. However, other underlying factors, such as genetic risk, lifestyle habits, and previous cancer diagnoses can reduce this effect.

If you are concerned about your cancer risk, or already have cancer, your best option is to check in with your healthcare provider rather than relying on garlic consumption alone for prevention.

Are there side effects of raw garlic?

For most people, garlic is a safe, flavorful addition to make to any meal. But it's not without its own set of side effects, especially if you consume large amounts. Here are some potential side effects to watch for when eating raw garlic in particular, according to Dr. Li and Taub-Dix:

• Digestive issues: Eating raw garlic can lead to things like heartburn, acid reflux, and diarrhea, especially if you're already prone to stomach problems.
• Bad breath and body odor: Garlic’s strong aroma might linger in your mouth longer than you'd like, leading to some pretty ripe breath. It can even change the smell of your sweat, making it a little smellier than usual.
• Blood thinning: In some cases, large amounts of raw garlic regularly can act like a blood thinner¹⁰, which can increase your bleeding risk overall.
• Medication interactions: Garlic can interfere with drugs like blood thinners, HIV medications, and certain medicines that help control blood sugar, among others.

If you’re taking any prescription meds or supplements, check with your healthcare provider before adding garlic or garlic supplements to your routine. For most people, a clove or two in your cooking is perfectly safe and might even come with some bonus health perks, says Dr. Li.

How much garlic should you eat per day?

If you feel a cold coming on and want to give raw garlic a go, try eating one to two cloves per day, Dr. Li says. Any more than that could increase the odds of acid reflux, an upset stomach, or that signature "garlic breath," he adds.

Here are some great ways to get the most out of those two cloves, per Dr. Li and Taub-Dix:

• Chop, crush, or mince the garlic to activate an enzyme called alliinase¹¹, which transforms garlic’s natural compound, alliin, into allicin (which, as we've learned, is the real immune-boosting powerhouse).
• Let it rest for 10 to 15 minutes after chopping to maximize its benefits. Think of it as garlic’s “air time” to power up.

And if raw garlic isn’t your jam, no problem. Taub-Dix suggests these gentler options:

• Crush garlic and make a tea with honey and lemon.
• Sauté chopped garlic in olive oil and toss it with your favorite veggies.
• Add crushed garlic to soups, broths, or sauces for a flavorful immune boost.

Pro tip: Cooked garlic has a milder taste and is less likely to give you "garlic breath," says Dr. Li. And if you prefer supplements? Garlic capsules and tablets are an option, but always check with your healthcare provider to avoid any drug interactions or side effects.

Other natural ways to relieve a cold

Not a garlic fan? No worries. Here are some other tried-and-true natural remedies from Dr. Li, Taub-Dix, and Johns Hopkins Medicine to help kick your cold to the curb:

1. Sip on some soup

Warm liquids like chicken soup or broth can remedy a sore throat, keep you hydrated, and even temporarily open your nasal passages due to the steam. Plus, it’s the ultimate comfort food during winter and peak cold season. You could even sip it from a mug like you would your morning coffee or tea.

2. Drink herbal tea with honey

Speaking of tea: Teas with ginger, turmeric, or honey tend to have both anti-inflammatory and antimicrobial properties. Not only will this help soothe your sore, inflamed throat and nasal passages, but also help keep you hydrated.

3. Load up on fruits and veggies

Sure, garlic can be a go-to if you sense a cold approaching, but loading up on plenty of fruits (like oranges, lemons, and berries) and veggies is just as important for maintaining optimal health. Plus, many fruits are packed with vitamin C, which can help support your immune system. Try adding citrus slices to tea for a hydration and vitamin boost.

4. Gargle with salt water

According to Johns Hopkins, gargling warm salt water can help reduce throat pain and swelling. Simply mix 1 teaspoon of salt in a mug of warm water, gargle over the sink, and spit.

5. Use a humidifier

Because dry air can irritate your throat, especially when sick, placing a humidifier in your bedroom while you sleep could help reduce your cold symptoms. If you don’t have a humidifier (like this one from LEVOIT, $30), try the at-home version, which is placing a bowl of water near a heat source—to add moisture to the air.

6. Get some rest

When you're feeling under the weather, your body needs plenty of rest to recover and heal. Try to rest as much as possible, which may include taking small naps, getting a full 7 to 9 hours of sleep per night, or staying in to recoup.

The bottom line

Garlic can be a helpful ally in fighting off a cold, but it’s not a cure-all. Recovery is all about balance—pairing healthy foods, proper hydration, and plenty of rest for the best results.

If your cold lingers beyond 10 to 14 days or your symptoms worsen, it might be time to see a healthcare provider. Keep an eye out for red flags like difficulty breathing, chest pain, high fever, dark phlegm, or severe dehydration, which may indicate a more serious issue beyond the common cold. Don’t hesitate to get medical help if needed—it’s always better to play it safe.