as well as with dietary supplements or medications based on garlic components
Historical Background
Garlic is a very ancient cultivated plant that is used worldwide today as a vegetable and seasoning. It was already used in ancient Indian medicine as a remedy for diseases such as “rheumatism and abdominal complaints,” as well as many other ailments. Garlic was also used as a food in ancient Egypt. The Greeks and Romans used garlic as a seasoning and are said to have used it in Olympia to fortify their athletes [2].
Chemical and pharmacological composition:
Allicin (allyl 2-propenethion sulfinate or diallyl thiosulfinate) is the most important bioactive component in aqueous extracts or garlic homogenates. It is produced from alliin through the activation of the enzyme allinase when garlic is chopped or grated. In an aqueous environment, allicin can spontaneously convert into allyl sulfides and diallyl sulfides. In the oil phase (e.g., in garlic oil macerates), the breakdown of allicin from crushed garlic produces organosulfur phytochemicals, vinyldithiins (70%), sulfides (18%), and ajoenes (12%) [2].
Uses of Garlic Preparations
Garlic (Allium sativum L) belongs to the lily family and grows to a height of 30–70 cm. A spherical bulb grows in the soil, surrounded by several smaller bulbs (“cloves”). Each garlic clove, individually and collectively, is enclosed in dry, whitish-reddish skins. The plant, which is native to Asia, is a close relative of wild garlic and the common onion and is now cultivated worldwide. Medicinally, garlic (Allium sativum L.) is traditionally used as garlic oil (for external application) or as fresh and dried bulbs.
The MMI Pharmidex Plus lists over 30 different garlic preparations. These include ready-to-use preparations such as garlic tablets or garlic coated tablets (e.g., Knoblauch Drg. Dr. Böhm®), as well as combination preparations with hawthorn or parsley, hawthorn and mistletoe, and garlic oil and ointment.
Garlic has been attributed with a variety of prophylactic and therapeutic effects—it is said to have antibacterial, antifungal, lipid- and blood sugar-lowering, anticoagulant, antioxidant, analgesic, and anti-inflammatory properties [2, 10].
Effects in vitro and in animal models
Garlic (Allium sativum) and its derivatives have been extensively studied in in vitro and in vivo animal models to evaluate their anti-inflammatory and immunomodulatory properties. It has been reported that garlic appears to enhance immune system function by stimulating macrophages, lymphocytes, natural killer (NK) cells, dendritic cells, and eosinophils through the modulation of cytokine secretion, immunoglobulin production, phagocytosis, and macrophage activation. It is believed that the garlic organic sulfur compounds (GOSCs), including γ-glutamyl-S-allyl-L-cysteines (GSACs), alliin, S-allylcysteines (SACs), diallyl sulfide (DAS), diallyl disulfide (DADS), diallyl trisulfide (DATS), and allicin, are responsible for garlic’s biological activities. Among the GOSCs, DATS stands out as a potential anti-inflammatory agent in both cellular and animal models by downregulating the NF-κB signaling pathway, which leads to the inhibition of transcription of several cytokine genes involved in pro-inflammatory responses. DATS has also been discussed as a potential phytochemical that inhibits TNF-α and histamine-induced inflammation by reducing the formation of reactive oxygen species (ROS) [4] .
Results of a PubMed search:
A PubMed search for scientific articles using the keyword "garlic" yielded 8,824 hits; 25 references were found for "garlic and rheumatic diseases" (as of June 20, 2025).
There is one double-blind RCT on RA; for knee osteoarthritis, 4 RCTs (3 double-blind, 1 single-blind) have been published, along with a total of 4 systematic reviews.
For the indication "metabolic syndrome" (e.g., obesity, diabetes mellitus, hyperlipidemia, arterial hypertension), results are available from 16 RCTs involving 999 participants, which indicate a preventive or therapeutic effect of garlic on TG, TC, BG, RR values, and associated biomarkers [9] . A systematic review and meta-analysis of RCTs on the effects of garlic on inflammatory biomarkers, which included a total of 16 studies in patients with predominantly metabolic diseases, found a significant reduction in CRP in only 3 of 13 evaluable studies; however, a significant decrease compared to placebo was detectable in the pooled analysis. This effect was primarily observed in patients with elevated baseline CRP, at dosages exceeding 1200 mg of garlic powder, in studies lasting more than 12 weeks, and with larger sample sizes [5].
Use of garlic in rheumatoid arthritis (RA)
Regarding the effects of garlic supplementation (1000 mg powder capsules, corresponding to 2.5 g of fresh garlic or 2.5 mg of allicin), Moosavian et al. published two studies reporting the results of a double-blind RCT involving 70 women with moderate to severe RA (DAS28 > 3.2). In this study, the DAS28, pain VAS, number of tender joints (TJC), number of swollen joints (SJC), fatigue, and serum levels of CRP and TNF-α decreased significantly in the garlic group (n=35) compared to the placebo group (n=35) [13, 14]. Furthermore, at the end of the study, a significant increase in total antioxidant capacity (TAC) and a significant decrease in malondialdehyde (MDA) were observed in the garlic group compared to the placebo group. VAS and HAQ scores also decreased in the garlic group compared to the placebo group [14]. No further randomized studies on RA or other inflammatory joint diseases are currently available. A recently published systematic review [8] also mentions an open-label study published in Russian in 1999 involving 30 RA patients, which resulted in an unspecified partial response in 86.7% of the 15 RA patients who received 300 mg of garlic extract twice daily for 4–6 weeks [7].
Use of Garlic for Osteoarthritis
An 8-week RCT study conducted by Hussein et al. compared the effects of a multimodal rehabilitation program with combined garlic therapy (900 mg/day) on the management of clinical manifestations and quality of life in 43 patients with knee osteoarthritis. After an 8-week intervention, a significant reduction in synovial cytokines, including IL-1β, IL-6, and TNFα, was observed only in the garlic group (n=28). This was accompanied by better control of knee pain and effusion, as well as improved muscle strength and quality of life. The study is currently available only as a poster. Significant differences were observed, suggesting a positive effect of garlic on the control of inflammation in knee osteoarthritis [12].
Another study investigated the effect of garlic supplementation (1000 mg/day) on symptom relief in 76 postmenopausal overweight or obese women with knee osteoarthritis. After 12 weeks of treatment, the WOMAC total score and its subscales improved significantly only in the garlic group, with the exception of the pain subscale, which also decreased in the placebo group. However, the changes in the WOMAC parameters showed no statistically significant differences between the two groups [15].
The same group of authors published another article with the same study design and sample, investigating the effects of garlic supplementation on the pro-inflammatory adipocytokine resistin, on TNF-α, and on pain intensity. After the intervention, serum concentrations of resistin had decreased significantly in the garlic group; no significant changes in TNF-α were observed in either group. Pain scores (VAS) had decreased significantly in the garlic group but not in the placebo group [6].
The same group investigated the efficacy of garlic supplementation (1000 mg/day) in 48 obese women with knee osteoarthritis in a further randomized, controlled study. At the end of the 12-week study, all clinical outcomes, including the WOMAC total score and its subscales as well as the VAS joint pain score, were significantly improved in the garlic group compared to the placebo group. However, no statistically significant differences were found between the groups [11].
Williams et al. published a cross-sectional study of a large population-based volunteer cohort of twins, in which the influence of dietary patterns on the development of coxarthrosis was investigated. Dietary intake was analyzed using a dietary questionnaire; osteoarthritis was determined using plain X-rays. The analyses were adjusted for age, BMI, and physical activity. In a subsequent in vitro study, the effects of compounds derived from Allium on the expression of matrix-degrading proteases in SW1353 chondrosarcoma cells were investigated. Depending on the phenotype, data were available for 654–1,082 of 1,086 female twins (mean age 58.9 years). Analysis of dietary patterns revealed that a high proportion of fruits and vegetables was inversely associated with coxarthrosis (p = 0.022). Consumption of “non-citrus fruits” (p = 0.015) and allium vegetables (p = 0.029) had the strongest protective effect [16].
Consuming garlic alters the odor of breath and skin, which some people find unpleasant. In addition, consumption can trigger heartburn and other gastrointestinal complaints (vomiting, nausea, diarrhea, colic). Allergic reactions have also been reported following garlic consumption; both allergic asthma and skin reactions have been observed after garlic consumption [1]. Allergies appear to occur more frequently in people who also suffer from pollen allergies.
Although there is no evidence that garlic affects pregnancy or breastfeeding, certain compounds may pass into breast milk.
Drug interactions have been reported with saquinavir, an HIV medication, whose effect may be reduced when taken concurrently [3].
Although the (few) available studies suggest that the consumption of garlic or garlic supplements may have an effect that supports the efficacy of standard therapy in RA and knee osteoarthritis, the Commission considers that the scientific evidence is insufficient to recommend the use of garlic extracts for symptoms associated with a defined inflammatory rheumatic condition.
Since garlic is a plant that is also used regularly and in large quantities in Mediterranean cuisine and for which anti-inflammatory effects have been demonstrated experimentally, garlic in its natural form can be recommended as a dietary component for patients with rheumatic diseases. This is particularly relevant in view of its positive effects on common comorbidities associated with rheumatic diseases.
1. Armentia A, Martin-Armentia S, Pineda F et al. (2020) Allergic hypersensitivity to garlic and onion in children and adults. Allergol Immunopathol (Madr) 48:232-236
2. Bayan L, Koulivand PH, Gorji A (2014) Garlic: a review of potential therapeutic effects. Avicenna J Phytomed 4:1-14
3. Borrelli F, Capasso R, Izzo AA (2007) Garlic (Allium sativum L.): adverse effects and drug interactions in humans. Mol Nutr Food Res 51:1386-1397
4. Charneca S, Hernando A, Costa-Reis P, Guerreiro CS (2023) Beyond Seasoning—The Role of Herbs and Spices in Rheumatic Diseases. Nutrients 15
5. Darooghegi Mofrad M, Milajerdi A, Koohdani F et al. (2019) Garlic Supplementation Reduces Circulating C-reactive Protein, Tumor Necrosis Factor, and Interleukin-6 in Adults: A Systematic Review and Meta-analysis of Randomized Controlled Trials. J Nutr 149:605-618
6. Dehghani S, Alipoor E, Salimzadeh A et al. (2018) The effect of a garlic supplement on the pro-inflammatory adipocytokines, resistin and tumor necrosis factor-alpha, and on pain severity, in overweight or obese women with knee osteoarthritis. Phytomedicine 48:70-75
7. Denisov LN, Andrianova IV, Timofeeva SS (1999) [The effectiveness of garlic in rheumatoid arthritis]. Ter Arkh 71:55-58
8. Freire De Carvalho J, Lerner A, Benzvi C (2025) Garlic Extract in Rheumatological Diseases: A Systematic Review. Complement Med Res 32:296-300
9. Fu Z, Lv J, Gao X et al. (2023) Effects of garlic supplementation on components of metabolic syndrome: a systematic review, meta-analysis, and meta-regression of randomized controlled trials. BMC Complement Med Ther 23:260
10. Hernandez-Cruz EY, Silva-Islas CA, Maldonado PD et al. (2022) Antinociceptive effect of garlic, garlic preparations, and derivative compounds. Eur J Pain 26:947-964
11. Hosseinzadeh-Attar MJ, Alipoor E, Dehghani S, Salimzadeh A (2020) Increased efficacy of a garlic supplement on knee osteoarthritis symptoms in patients with obesity. J Herb Med 24
12. Hussein NA, Sharara GM (2007) Poster 9: Effect of Combined Garlic Therapy and Comprehensive Rehabilitation Program Versus Comprehensive Rehabilitation Program Alone on Control of Clinical Manifestations and Quality of Life of Knee Osteoarthritis Patients. Archives of Physical Medicine and Rehabilitation 88:E12
13. Moosavian SP, Paknahad Z, Habibagahi Z (2020) A randomized, double-blind, placebo-controlled clinical trial evaluating the effects of a garlic supplement on certain serum biomarkers of oxidative stress and quality of life in women with rheumatoid arthritis. Int J Clin Pract 74:e13498
14. Moosavian SP, Paknahad Z, Habibagahi Z, Maracy M (2020) The effects of garlic (Allium sativum) supplementation on inflammatory biomarkers, fatigue, and clinical symptoms in patients with active rheumatoid arthritis: A randomized, double-blind, placebo-controlled trial. Phytother Res 34:2953-2962
15. Salimzadeh A, Alipoor E, Dehghani S et al. (2018) The effect of 12-week garlic supplementation on symptom relief in overweight or obese women with knee osteoarthritis. Int J Clin Pract 72:e13208
16. Williams FM, Skinner J, Spector TD et al. (2010) Dietary garlic and hip osteoarthritis: evidence of a protective effect and putative mechanism of action. BMC Musculoskelet Disord 11:280
Last updated: March 10, 2026