This review from 2013 examines the pharmacological effects of A. sativum, A. hirtifolium, and their active constituents. Garlic extracts were examined for antimicrobial, cardiovascular, lipid and immune effects.
Concluding a high tolerance and low risk for consumption of garlic extracts particularly with standardized allicin content.
Mikaili P, Maadirad S, Moloudizargari M, Aghajanshakeri S, Sarahroodi S. Therapeutic uses and pharmacological properties of garlic, shallot, and their biologically active compounds. Iran J Basic Med Sci. 2013 Oct;16(10):1031-48. PMID: 24379960; PMCID: PMC3874089.