The invention includes a method of treating gastrointestinal diseases associated with species of genus Clostridium such as clostridium deficit in human patients with gastrointestinal disorders having an etiological component such as a microbial agent producing a toxin where treated with an antimicrobial composition an amount effective to inhibit or eliminate the microbial agent. The antimicrobial composition in a form of probiotic mixture can be administrated alone or in combination with an antimicrobial agent, such as a bacteriophage which is specific for a bacterium producing toxin or antibiotics which are then used to eliminate or inhibit the clostridial species overgrown in a patient's gastrointestinal tract. Disorders that can be treated by the method of the invention include diarrhea or inflammatory bowel diseases such as colitis or Crohn's disease.
