Garlic is a pungent, bulb-shaped vegetable belonging to the same plant family as onions, leeks, and chives. Scientifically known as Allium sativum, it’s one of the oldest cultivated crops on Earth, grown for at least 5,000 years and used across virtually every major cuisine. The bulb grows underground and is divided into individual segments called cloves, each wrapped in a papery skin. It’s valued both as a kitchen staple and for a range of well-documented health properties.
Where Garlic Comes From
Wild garlic still grows in Central Asia, centered in modern-day Kyrgyzstan, Tajikistan, Turkmenistan, and Uzbekistan. That’s where humans first began cultivating it. Ancient Egyptian and Indian cultures referenced garlic around 5,000 years ago, and the Babylonians were using it 4,500 years ago. Chinese records suggest garlic cultivation began there roughly 4,000 years ago. From Central Asia, garlic spread along trade routes until it became a global crop.
Today, world production tops 29 million metric tonnes annually. China dominates, growing about 73% of the global supply. India is a distant second at around 3.2 million tonnes, followed by Bangladesh, Egypt, and Spain. The United States produces roughly 205,000 tonnes a year, most of it from California.
What Happens When You Crush a Clove
Garlic’s sharp smell and flavor aren’t present inside an intact clove. They’re created the moment you cut, crush, or chew it. Damaging the cells releases an enzyme that triggers a rapid chemical reaction, converting a dormant sulfur compound into a potent, short-lived molecule called allicin. This reaction is fast: it finishes within 10 to 60 seconds of crushing. Allicin is responsible for that unmistakable garlic bite, and it’s also the compound behind many of garlic’s health effects.
Heat destroys the enzyme that makes this reaction possible. If you toss a whole, uncrushed clove into boiling water or a hot oven for six minutes or more, it loses the ability to produce allicin entirely. But if you crush the garlic first and let it sit briefly before cooking, many of those beneficial compounds form before the heat can shut the process down. Cooking at high temperatures for more than 10 minutes breaks down the active compounds regardless, which is why roasted garlic tastes mellow and sweet compared to raw.
Two Main Types: Hardneck and Softneck
All garlic falls into two broad categories, and the distinction matters if you’re cooking with it or growing it.
- Hardneck garlic has a stiff central stalk and produces a curly green shoot called a scape. It offers a stronger, more complex flavor with a hint of spiciness. It needs cold winters to develop properly, making it the better choice for northern climates. The tradeoff is shelf life: hardneck keeps for only about 3 to 6 months.
- Softneck garlic is the type you typically find in grocery stores. It has a milder, more subtle flavor and a flexible stalk (which is why it’s used for braiding). It prefers warmer climates and doesn’t need a cold period to grow. Softneck stores well, lasting 6 to 12 months under the right conditions.
Health Effects Worth Knowing About
Garlic has been studied extensively for its effects on heart health, particularly blood pressure. A large meta-analysis published in Frontiers in Nutrition found that garlic supplementation lowered systolic blood pressure (the top number) by about 4.2 mmHg and diastolic pressure (the bottom number) by about 3.1 mmHg compared to a control group. That may sound modest, but a drop of that size at the population level is enough to meaningfully reduce heart disease risk.
The sulfur compounds in garlic also have antimicrobial and anti-inflammatory properties. Regular garlic consumption has been linked to improved cholesterol profiles and better blood sugar regulation, though most of the stronger evidence comes from garlic supplements rather than the amounts you’d typically eat in food. Cooking reduces these effects, so raw or lightly cooked garlic delivers more of the active compounds.
Interactions With Medications
In the amounts used in cooking, garlic is safe for most people. But concentrated garlic supplements can interact with several types of medication. High-dose garlic increases the risk of bleeding if you’re taking blood-thinning medications like warfarin. It can amplify the effect of blood pressure drugs, potentially dropping your pressure too low. It may also lower blood sugar more than expected when combined with diabetes medications.
Garlic supplements can reduce the effectiveness of certain HIV medications and interact with immunosuppressive drugs used after organ transplants, potentially causing liver damage. If you’re on any of these medications, supplement-strength garlic is the concern, not the clove or two in your dinner.
Garlic Is Toxic to Dogs and Cats
One thing many pet owners don’t realize is that garlic is significantly more dangerous to dogs and cats than onions. Garlic is 3 to 5 times more toxic than onion on a weight-for-weight basis. The sulfur compounds that give garlic its health benefits in humans destroy red blood cells in cats and dogs, leading to a condition called hemolytic anemia. Cats are especially vulnerable. Even small amounts cooked into food can be harmful, so keeping garlic (and anything made with it) away from pets is important.