OBJECTIVE To understand the drug resistance of causative bacteria from the intestinal tract dysbacteriosis of the iatrogenic diarrhea patient,and to provide basis for choose the medicine for the clinical treatment of Ⅲ degree intestinal tract dysbacteriosis and internal infection caused by different causative bacteria. METHODS VITEK-ATB system was used to analyze and calculate the causative bacteria and their drug resistance from the intestinal tract dysbacteriosis of the iatrogenic diarrhea patient in the hospital from 2001 to 2003. RESULTS Causative bacteria for intestinal tract dysbacteriosis in order were enterococci(31.90%),yeast-like fungi(27.24%),Proteus(16.34%),Pseudomonas aeruginosa(6.23%),Citrobacter(5.84%),Klebsiella(5.45%),toxin A producing Clostridium difficile(5.06%),and Staphylococcus aureus(1.94%).The yeast-like fungi had no drug resistance to amphotericin B and nystatin,the P.aeruginosa,Proteus and Klebsiella had no drug resistance to imipenem and meropenem,80% S.aureus were MRSA,and had no drug resistance to minocycline,nitrofurantoin,fusidic acid,vancomycin,teicoplanin and quinupristin-dalfopristin. CONCLUSIONS In the process of treatment Ⅲ degree intestinal tract dysbacteriosis and interior-infection caused by different causative bacteria,choosing different sensitive medicine could remove the specific causative factors of the disease.