This study demonstrates that enteric-coated garlic powder supplements with 9.6 mg allicin-releasing potential may have value in mild to moderate hypercholesterolemic patients when combined with a low-fat diet. Results suggest that garlic supplementation has a cholesterol lowering effect, which may be mediated by direct action of a biologically active compound or compounds and, in part, through the effect on food and nutrient intake.

Compared with placebo, garlic preparations may lead to small reductions in the total cholesterol level at 1 month and at 3 months, but not at 6 months. Changes in low-density lipoprotein levels and triglyceride levels paralleled total cholesterol level results; no statistically significant changes in high-density lipoprotein levels were observed. Trials also reported significant reductions in platelet aggregation and mixed effects on blood pressure outcomes.

Allicin in its pure form was found to exhibit 1) antibacterial activity against a wide range of gram-negative and gram-positive bacteria, including multidrug-resistant enterotoxicogenic strains of E. coli, and 2) antifungal activity and antiviral activity. The main antimicrobial effect of allicin is due to its chemical reaction with thiol groups of various enzymes, which can affect essential metabolism of cysteine proteinase activity involved in the virulence of E. histolytica.

Forty-two healthy adults with a serum total cholesterol level of greater than or equal to 220 mg/dL received, in a randomized, double-blind fashion, 300 mg three times a day of standardized garlic powder in tablet form or placebo. The results showed a baseline serum total cholesterol level of 262 reduced was reduced to 247 after 12 weeks of standard garlic treatment. Corresponding values for placebo were 276 before and 274 after. There were no significant changes in high density lipoprotein cholesterol, triglycerides, serum glucose, blood pressure, and other monitored parameters.

An allicin-containing supplement can prevent attack by the common cold virus. One hundred forty-six volunteers were randomized to receive a placebo or an allicin-containing garlic supplement, one capsule daily, over a 12-week period. They used a five-point scale to assess their health and recorded any common cold infections and symptoms in a daily dairy. The active-treatment group had significantly fewer colds than the placebo group. They are also less likely to get a cold and recovered faster id infested. An allicin-containing supplement can prevent attack by the common cold virus.