We have shown that a specific component of supercritical (SC) garlic extract and some synthetic disulfide analogs are active as antimicrobials. In the course of this study, six compounds (diallyl disulfide, 1-propenylallyl disulfide, methylallyl disulfide, diallyl trisulfide, 2-vinyl-4H-1,3-dithiin, and 3-vinyl-4H-1,2-dithiin) were isolated from SC garlic extract and identified. Also, two novel sulfoxide-containing garlic analogs were synthesized. All isolated and synthetic substances were tested as potential antimicrobials against gram-positive bacteria Bacillus cereus, Mycobacterium smegmatis, and Micrococcus luteus and gram-negative bacteria Pseudomonas aurantiaca. Diallyl disulfide and diallyl trisulfide exhibited the best activity against both gram-positive and gram-negative bacteria.