Formulation for the treatment of cancer comprising a bacterial extract

A bacterial formulation, for use in the treatment or prevention of cancer, comprises, together with at least one pharmaceutically acceptable diluent, carrier or adjuvant, an active ingredient selected from (i) and (ii), namely: (i) at least three oncolytic strains of bacteria from at least two bacterial species, wherein said strains are obtainable or derivable from human intestinal microflora; and (ii) at least one oncolytic strain of bacteria selected from Escherichia coli A.T.C.C. 55373, Escherichia coli A.T.C.C. 55374, Escherichia coli A.T.C.C. 55375 and Streptococcus faecalis G35 A.T.C.C. 55376. The specified strains are also the subject of the invention.