The communication summarizes mainly newly obtained experimental findings confirming the antibacterial effect of garlic preparations (powders, extracts, juice, essential oil, oil macerate) and their individual components. It also reports the effectiveness of substances newly isolated from the oil macerate (iso-E-10-devinylajoene, Z-10-devinylajoene, and three, or five thiosulfinates). The effect on the tested bacteria included here is, according to new evidence, indisputable. The paper has purposefully excluded the action of garlic against the widely distributed bacteria Helicobacter pylori, which causes chronic gastritis, gastric and duodenal ulcers. The findings concerning this matter will be published in the following communication.