“…Tetracycline depresses the protein metabolism of mammalian cells (Edwards, Huskisson, and Taylor, 1970), and neomycin, at least in large doses, can itself induce malabsorption (Dobbins, Herrero, and Mansbach, 1968). Nevertheless the remarkable responses to antibacterial therapy sometimes obtained, together with other evidence from quantitative studies of the upper gut flora, provide us with reasons for believing that man's intestinal microflora may influence his state of health sometimes to his benefit, more often (or at least more often recognized) to his detriment.…”