This invention relates to controlled release formulations of probiotic bacteria and bacteriophages, including combined formulations of probiotic bacteria and bacteriophages. The formulations contain a hydrophilic agent, an electrolytic agent and a polysaccharide and may be in tablet form for oral delivery to the intestinal system. In one preferred aspect, the formulations of the present invention effect the simultaneous introduction or addition of probiotic bacteria and bacteriophages to cause the subtraction or removal of undesirable bacteria.