This is what I read "Bacillus subtilis remains one of the most potent and beneficial of all health-promoting and immune-stimulating bacteria. According to clinical studies documented in the medical research report, IMMUNOSTIMULATION BY BACILLUS SUBTILIS PREPARATIONS, by micro-biologist J. Harmann, the cell wall components of ingested Bacillus Subtilis are able to activate nearly all systems of the human immune defense, including the activation of at least three specific antibodies (IgM, IgG and IgA secretion) which are highly effective against many of the harmful viruses, fungi and bacterial pathogens which regularly attempt to invade and infect the human system"