The bacterial flora of the small intestine is still not fully understood. This is also due to the fact that a lot of these gut inhabitants aren't cultivable. PCR-TGGE (Temperature Gradient Gel Electrophoresis) is a molecular tool by which the 16S ribosomal DNA of a bacterial community can be studied for its diversity. Based on sequence differences in the variable region V6-V8, 16S ribosomal DNA fragments are separated during a TGGE run. This study shows that PCR-TGGE is a valuable tool as it gives additional information about the flora composition that could not be found with classical bacteriological techniques.