Abstract
Specimens of mucosal tissue of the small and large bowel obtained either by a colonoscope or during surgical operations were investigated quantitatively for their bacterial flora. A detailed prescription of the methodology using an anaerobic chamber is given. Most of the mucosal specimens of the small intestine as well as all the specimens of the large intestine contained bacteria (about 104 germs/g). Predominantly, Bacteroides, gram‐positive rods, and cocci were isolated. In contrast to the gut lumen flora anaerobic bacteria of the mucosal flora did not outnumber the aerobes. In patients with inflammatory bowel disease or with carcinoma of the colon the mucosal flora showed no demonstrable alterations even after undergoing a sulphonamide therapy.