Allicin, in garlic, provides innumerable health benefits which include combating cold and cough, lowering blood pressure, fighting heart ailments, and preventing Alzheimer’s. It also helps relieve earaches, treat intestinal issues, cure wounds, prevent cancer, and relieve excess gas.
What is Garlic?
Garlic (Allium sativum) is a strong-smelling, pungent-tasting herb. It is a close relative of onionand is native to Central Asia. It has been used as a food-flavoring agent and as a traditional medicine. Mankind recognized the curative qualities of this magic herb over 3,000 years ago. Sir Louis Pasteur, the scientist who discovered pasteurization, effectively utilized the anti-bacterial qualities of this herb all the way back in 1858.  A report in the Journal of Pharmaceutical Research suggested that while one clove per day may bring a vast improvement in your overall health, 2 to 3 cloves could prevent an attack of the common cold.  World War I medical surgeons also used the garlic juice as an antiseptic for treating war wounds.
Garlic contains useful minerals such as phosphorus, potassium, magnesium, zinc, calcium, and iron, as well as trace minerals like iodine, sulfur, and chlorine. According to the USDA National Nutrient Database, it is a rich source of vitamins like folate, thiamine, niacin, and vitamin C, A, K, and B6. In terms of organic compounds, it is one of the rare sources of allicin, allisatin 1, and allisatin 2.  The herb is very low in calories, saturated fats, and sodium.
Benefits of Raw Garlic
The health benefits of eating raw garlic cloves are explained in greater detail below.
Treats Cold and Cough
A 2014 paper published in the Cochrane Database of Systematic Reviews cited a study that assessed 146 participants over a three‐month period to ascertain the impact that garlic had on patients suffering from cold and cough.  As part of the study, the total number of participants were divided into two equal groups. While one group took a placebo tablet, the other group took a garlic tablet at the same time. At the end of the study, it was noted that people who took garlic every day for three months instead of a placebo had fewer bouts of cold.
To elaborate, there were 24 occurrences of the common cold in the garlic group, over the three-month period, as compared to 65 in the placebo group. The length of illness, however, was more or less similar in both groups, with the former lasting for 4.63 days and the latter lasting for 5.63 days.
This, thus, proves that eating raw garlic cloves helps treat colds and coughs. At the very onset of a cold eating, at least two crushed cloves may help in lessening the severity of your cold.
Garlic is an herbal ingredient for lowering high blood pressure. When exposed to high levels of pressure, the allicin present in it relaxes the blood vessels. It also fights against thrombosis by reducing platelet aggregation.
Lowers Cholesterol Levels
Raw garlic, rich in the allicin compound, effectively prevents LDL (bad) cholesterol from oxidizing. All those who have high cholesterol levels should include this herb in their daily diet.
Boosts Heart Health
Regularly eating raw garlic cloves help prevent thromboembolism. This means they reduce blood clots and promote better blood flow. They also have significant cardioprotective properties which help prevent diseases like atherosclerosis, hyperlipidemia, thrombosis, hypertension, and more. Dr. Sanjay K Banerjee, Department of Pharmacology, All India Institute of Medical Sciences published a report in the Nutrition Journal that supports the proposal that garlic consumption has a significant cardioprotective effect, which includes both animal and human studies. However, one should keep a close tab on the proper use of garlic i.e. use of different preparations available, dose, duration and its interaction with generic drugs. 
Prevents Alzheimer’s & Dementia
Prevents Heavy Metal Poisoning
High doses of garlic can prevent organ damage caused by heavy metals. The sulfur compounds in this herb drastically reduce lead levels in the blood. Additionally, it also prevents the signs of toxicity such as headaches and blood pressure. Sulfur also aids in better absorption of iron and zinc in the blood. On the other hand, a 2012 report published in the Basic and Clinical Pharmacology and Toxicology reveals that garlic is effective in reducing blood and tissue lead concentrations among human beings and animals alike. 
It acts as an effective herbal treatment for the infected wound. Place 2 crushed cloves on the infected area to get instant relief.
Herbs like garlic and onion impact estrogen levels in menopausal women, preventing the risk of osteoarthritis.  They also minimize bone loss and improve overall bone health.
Daily inclusion of raw garlic cloves in your diet aids in eliminating digestive problems. Even inflammation or irritation of the gastric canal may be reduced using this herb. Garlic helps clear up most intestinal problems like dysentery, diarrhea, and colitis. Its role in dispelling worms is phenomenal. It does not affect the good bacteria in the intestine but destroys the harmful ones. It not only enhances digestion but also helps relieve stomach gas.
Regulates Blood Sugar
Boosts Immune System
Garlic has phytonutrients that help reduce oxidative stress, and prevent DNA damage, thereby, strengthening your immunity. Furthermore, the herb reduces fatigue, as well as increases energy and longevity. A 2012 report published in the African Journal of Traditional, Complementary and Alternative Medicines revealed a study that was conducted on rats to ascertain if garlic plays a contributory role in enhancing immune function.  After garlic (Allium sativum) extracts were administered to rats at different concentrations it was discovered that the extracts, especially at higher concentration, showed more immune-stimulating effects.
Relieves Ear Aches
This herb is commonly used for curing earaches and ear infections due to its antiviral, antifungal, and antibiotic properties.
Garlic, along with other ingredients like honey, cream, and turmeric, can be used to treat acne scars and prevent the onset of acne.  This herb is an effective skin cleanser and an antibiotic substance that helps treat many skin conditions. These include skin rashes, psoriasis, cold sores, and blisters. Additionally, it also helps in cell synthesis, protecting against UV rays, and in delaying aging.
Boiled garlic cloves are effective in treating asthma. Each night before going to sleep, drinking a glass of milk with 3 boiled cloves of this herb can bring subsequent relief for patients with asthma. The asthma attacks may be brought under control by having crushed cloves with malt vinegar as well. Additionally, they can also be used to treat lung infections like cystic fibrosis.
The herb has certain aphrodisiac properties, so it can be utilized as an effective rejuvenator for sex. The health benefits of this herb are further known to enhance the libido of both men and women. People who tend to overindulge in sexual activities should consume garlic to protect themselves from nervous fatigue.
A 2013 report published in the Journal of Neuro-Oncology revealed that garlic contains a compound called diallyl trisulfide (DATS) that is an effective therapeutic agent in preventing tumor progression.  Thus regular intake of garlic reduces the risk of colon, bladder, lung, prostate, stomach, brain, esophagus, and liver, cancer. It aids in reducing the production of carcinogenic compounds, and also reduces the occurrence of tumors associated with breast cancer.  
Prevents Peptic Ulcer
The antibacterial compounds present in garlic can eliminate stomach parasites that cause peptic ulcers.
Garlic aids in weight loss and reducing obesity. It reduces the expression of genes that are involved in adipogenesis, which leads to the formation of fat cells.  The herb increases thermogenesis, which helps burn fat and reduce LDL (bad) cholesterol levels. 
Prevents Fatty Liver
Treats UTI and Kidney Infections
Garlic prevents the growth of Pseudomonas aeruginosa, a pathogen responsible for recurring urinary tract infections (UTI) and kidney infections.   Additionally, fresh garlic extract is also used to prevent the growth of candida vaginitis and E. coli infection.  
Prevents Hair Loss
The herb helps in preventing hair loss and promoting hair growth. Regular application of garlic gel or garlic-infused coconut oil can also aid in treating alopecia.
Antibacterial and Antiparasitic Effects
Garlic extracts help treat Heliobacter pylori infection,tick, bites, jock itch, and athlete’s foot. [] It also helps to eliminate tapeworm and ringworm.
Traditionally, garlic has been used to treat stubborn splinters. Place a cut piece of its clove over the splinter cut, bandage it, and see the splinter and pain disappear!
How to Use?
The herb can be consumed raw but the taste is so potent that people usually prefer cooking it or adding it to various dishes.
- It can be chopped, crushed, sliced, or juiced. Cutting garlic activates alliinase enzymes which are highly beneficial to health.
- You can use it in salads, soups, stews, vegetable, fish, and meat
- The herb is also an essential ingredient in various toothpaste and mouthwashes as it prevents tooth cavity and oral bacteria.
Word of Caution : Excess intake of this herb may cause irritation in the digestive system. The only drawback is its pungent smell and taste that leaves bad breath, but other than that, garlic is a medicinal boon for mankind!
Source: Organic Facts