Garlic (Allium sativum L.)

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Garlic is an herb widely used for the treatment and prevention of heart disease and cancer. Research suggests that tablets with dehydrated garlic powder may modestly reduce total cholesterol for up to 12 weeks. Garlic's long-term effects on cholesterol and heart health remain unclear.
Early evidence suggests that garlic may slightly reduce blood pressure and prevent blood clotting. Several studies report that regular consumption of garlic (particularly unprocessed garlic) may reduce the risk of several cancer types, including stomach and colon.
Multiple cases of bleeding have been associated with garlic use. Caution is warranted in people who are at risk of bleeding and before some surgical and dental procedures.

Related Terms

2-propenesulfenic acid, AGE, aged garlic extract, aglio (Italian), aglio commune (Italian), ail (French), ail blanc (French), ail commun (French), ail cultivé (French), ail de printemps (French), ail rose sans bâton (French), ajo (Spanish), ajo común (Spanish), ajo vulgar (Spanish), ajoene, akashneem, alho (Portuguese - Portugal, Portuguese - Brazil), ), alho-bravo (Portuguese - Brazil), alho-comum (Portuguese - Brazil), alho-hortense (Portuguese - Brazil), alisat, alk(en)yl thiosulfates, Alliaceae (family), allicin, Allicor® (a long-action, garlic-based preparation), Allii sativi bulbus, alliinase, allitridium, allium, allyl mercaptan, Alterswurzel (German), alubosa elewe, Amaryllidaceae (family), ayo-ishi, ayu, banlasun, bawang (Tagalog), bawang bodas (Sundanese), bawang puteh (Malay), bawang putih (Malay - Indonesia, Malay - Java), beli luk (Serbian), bellulli (Kannada), bhabang poté (Madurese), ca suan (Chinese), ca suan tou (Chinese), camphor of the poor, česen (Slovenian), cesnak kuchynský (Slovenian), česnek kuchyňský (Czech), česnek kuchyňský pravý (Czech), češnjak (Croatian), chesnok (Russian), chyet thon phew (Burmese), clove garlic, czosnek (Polish), czosnek pospolity (Polish), dai toan, da-suan, dasuan, dawang, diallyl disulphide (DADS), diallyl sulfide (DAS), diallyl sulphide, diethyl disulfide, diethyl hexasulfide, diethyl monosulfide, diethyl pentasulfide, diethyl tetrasulfide, diethyl trisulfide, dipropyl disulphide, dipropyl sulphide, dra thiam, (E)-ajoene, echter Knoblauch (German), fokhagyma (Hungarian), foom, gaarikku (Japanese), garlic clove, garlic corns, garlic extract, garlic oil, garlic paste, garlic powder extract, Gartenlauch, gemeiner Knoblauch (German), gewöhnlicher Knoblauch (German), hom khaao, hom kia, hom thiam (Thai), hua thiam, hvid-løg (Danish), hvidløg (Danish), hvitløk (Norwegian), hvitlök (Swedish), kath'ièm (Laotian), kesumphin, khtüm sââ (Khmer), kitunguu-sumu (Swahili), kitunguu-sumu, Knoblauch (German), Knöblich (German), Knofel (German), knoflook (Dutch), Knuflauk (German), Knuflook (German), konofló (Papiamento - Curaçao), kra thiam, krathiam (Thai), krathiam cheen, krathiam khaao, küüslauk (Estonian), Kwai®, Kyolic®, lahasun (Hindi), lahsan (Hindi), lahsun, lai, l'ail, la-juan, larsan (Hindi), lasan, lashun, lashuna (Kannada), lashunaa (Sanskrit), la-suan, lasun (Hindi, Nepalese, Punjabi), lasuna, lasuun (Marathi), lauch, lay, layi, lehsun (Urdu), lesun, Liliaceae (family), lobha, luk chesnok (Russian), luk posevnoi (Russian), ma nul (Korean), majo, methyl allyl, naharu, nectar of the gods, ninniku (Japanese), pa-se-waa, poor man's treacle, purgar garlic, PurGar garlic, rason, rasonam, rasun (Bengali), rocambole, rust treacle, rustic treacles, S-alk(en)yl cysteine sulfoxide, S-allylcysteine (SAC), sarımsak (Turkish), sarmesak (Turkish), sarmusak (Turkish), saum (Arabic), seer (Persian), sekhdor (Aremenian), shoum (Hebrew), shum (Hebrew), sir (Persian), skorda (Greek), skordo (Greek), skordon (Greek), skortho (Greek), sluon, Stinkerzwiebel (German), stinking rose, suan (Chinese), sudulunu (Sinhalese), tafanuwa, ta-suam, ta-suan, tellagada, tellagaddalu (Telugu), tetrasulfides, thawm (Arabic), thiam, thioallyl derivative, thiosulfinates, thoum thum (Arabic), t?i (Vietnamese), toi thum, toom (Arabic), toum (Arabic), trisulfides, tum, umbi bawang putih, vallaippundu (Finnish), velluli (Telugu), vallaippundu (Malayalam), vellaippuuntu (Tamil), vellaypoondoo (Tamil), vellulli (Telugu), verum, vinyl dithiin, vinyldithiin, vitloek (Swedish), vitlök (Swedish), vitløk (Swedish), wullaypoondoo (Tamil), (Z)-ajoene.
Combination products: Karinat® (beta-carotene 2.5 milligrams, alpha-tocopherol 5 milligrams, ascorbic acid 30 milligrams, and garlic powder 150 milligrams per tablet).

evidence table

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.
 
High blood pressure (Grade: A)
Numerous human studies report that garlic may lower blood pressure, particularly systolic blood pressure. It is unclear if effects are more pronounced in people with high blood pressure vs. normal blood pressure.
High cholesterol (Grade: A)
Multiple studies in humans have reported small reductions in total blood cholesterol and low-density lipoproteins (LDL or "bad" cholesterol) over short periods of time. Garlic lacks effects on high-density lipoproteins (HDL or "good" cholesterol).
Heart disease (risk) (Grade: B)
Several studies have concluded that garlic may have a positive impact on heart disease risk. Evidence suggests that garlic may reduce the incidence of heart attack or cardiac death.
Antibacterial (Grade: C)
Preliminary evidence suggests that garlic may be beneficial against oral microorganisms like
Anti-fungal (Grade: C)
Several studies describe garlic applied to the skin to treat fungal infections, including yeast infections. Additional research is needed before a conclusion can be drawn.
Atherosclerosis ("hardening" of the arteries) (Grade: C)
Research suggests modest short-term reductions in total cholesterol and low-density lipoprotein (LDL or "bad" cholesterol) levels with garlic supplements. Insufficient evidence exists on the effects of garlic on arthrosclerosis prevention or treatment. Further research is warranted in this area.
Athletic injuries (Grade: C)
Based on preliminary study, allicin (the major biologically active component of garlic) supplementation may reduce exercise induced muscle damage. The mechanism may be associated with allicin's antioxidant effects. Further studies are needed to confirm these findings.
Athletic performance (Grade: C)
A single dose of garlic has increased endurance performance. Long-term use of garlic for this purpose should be investigated.
Benign breast diseases (Grade: C)
Preliminary research suggests a garlic combination supplement may improve symptoms of benign breast disease. Additional study is needed using garlic alone.
Cancer (Grade: C)
Preliminary human studies suggest that regular consumption of garlic (particularly unprocessed garlic) may reduce the risk of several cancer types, including gastric and colorectal cancer. Further well-designed studies are needed in this area.
Chest pain (angina) (Grade: C)
Preliminary evidence suggests that garlic reduces chest pain by relieving spasm of the heart vessels and preventing blood clots. Additional studies are needed before a conclusion can be made.
Chronic venous ulcers (ulcers from poor circulation) (Grade: C)
A study has reported benefits from a combination garlic therapy on venous ulcers. Further research is warranted on this topic.
Circulation (Grade: C)
Garlic supplementation has increased calf blood flow in healthy people. Further research is needed before conclusions can be made.
Common cold / upper respiratory tract infection (Grade: C)
Preliminary reports suggest that garlic may reduce the severity of upper respiratory tract infections. In non-human studies, garlic has displayed anti-bacterial and anti-viral properties. Additional research is needed in this area.
Cystic fibrosis (Grade: C)
Garlic has been studied in combination with other therapies for cystic fibrosis. Further research is warranted.
Dental conditions (Grade: C)
The dental effects of garlic have been studied. Further research is needed before firm conclusions may be made.
Familial hypercholesterolemia (inherited high cholesterol) (Grade: C)
Familial hypercholesterolemia is a genetic disorder in which very high cholesterol levels are inherited. The effect of garlic on familial hyperlipidemia is unclear. Further research in this area is needed to draw a conclusion.
Gastric cancer prevention (Grade: C)
Garlic has been studied for its use in gastric lesions. Further research is needed before firm conclusions may be made.
Gastritis (inflammation of stomach) (Grade: C)
Preliminary evidence suggests that a combination product with garlic (Karinat®) may be beneficial for manging chronic atrophic gastritis, a precursor of stomach cancer. Additional evidence is needed before a conclusion can be made.
Hair loss (Grade: C)
Application of garlic gel on the skin may be beneficial for treating hair loss. Additional study is needed on this topic.
Heart disease prevention (secondary) (Grade: C)
Research suggests modest short-term reductions in total cholesterol and low-density lipoprotein levels (LDL or "bad" cholesterol) with oral garlic supplements. Long-term effects on lipids and atherosclerosis are unclear. There is limited evidence regarding the effects of garlic on heart attack, cardiac morbidity and mortality.
Heavy metal/lead toxicity (Grade: C)
Garlic's role in improving clinical manifestations of lead poisoning has been studied. Further research is warranted.
Helicobacter pylori infection (Grade: C)
In non-human studies, garlic has shown activity against bacteria and viruses. Several human case studies have examined the effects of garlic on
Hepatitis (Grade: C)
The effect of a hepatitis medication plus garlic oil has been studied. Further research of garlic alone is warranted.
Hepatopulmonary syndrome (Grade: C)
Hepatopulmonary syndrome is shortness of breath in people with liver disease. Garlic has been studied in people with hepatopulmonary syndrome. Further research is needed before firm conclusions may be drawn.
Mosquito repellent (Grade: C)
A preliminary study lacked support regarding garlic consumption for repelling mosquitoes. Well-designed clinical trials are required before conclusions may be made.
Otitis media (middle ear infections) (Grade: C)
Preliminary evidence suggests that a combination product containing garlic may be beneficial for ear pain caused by middle ear infections. Additional evidence is needed before a conclusion may be made.
Parasitic infections (Grade: C)
Experts suggest that international travelers eat fresh garlic to prevent intestinal parasites. There are mixed results regarding the use of garlic in the treatment of parasitic infections. Further evidence is needed before a conclusion may be made.
Peripheral vascular disease (narrowed arteries in the legs) (Grade: C)
Research suggests modest short-term reductions in total cholesterol and low-density lipoprotein levels (LDL or "bad" cholesterol) with oral garlic supplements. There is currently insufficient evidence demonstrating effects of garlic on peripheral vascular disease. Further research is warranted in this area.
Pre-eclampsia (high blood pressure in pregnancy) (Grade: C)
In the available research, garlic administration lacked significant effects on the incidence of preeclampsia, systolic or diastolic blood pressure. Well-designed studies are still required.
Sickle cell anemia (Grade: C)
Initial evidence suggests that aged garlic extract may reduce the number of damaged red blood cells in patients with sickle-cell anemia. Well-designed clinical trials are required before conclusions may be made.
Systemic sclerosis (thickening of skin) (Grade: C)
Preliminary evidence suggests that dried garlic powder may benefit people with systemic sclerosis. Well-designed clinical trials are required before conclusions may be made.
Tick repellant (Grade: C)
Early research has reported fewer tick bites in people receiving garlic. However, there is a lack of sufficient data for or against the use of garlic as an insect repellent.
Type 2 diabetes (Grade: C)
It is unclear if garlic may decrease glucose concentrations and increase insulin secretion. Additional research is needed in this area.
Warts (Grade: C)
According to preliminary research, garlic extract applied to the skin may be beneficial in treating warts and corns. This effect may be due to garlic's antiviral, immune-stimulating, or blood clot prevention properties. Further research is needed.