Ninety-three patients with suspected small bowel disease were investigated by duodenal forceps biopsy via a fiberoptic endoscope. Three biopsies were usually taken from the distal end of the second part of the duodenum, orientated on a square of plastic mesh, and examined by stereomicroscopy and histology. There were no failures or complications. Using strict criteria, sections from 56% of the 299 biopsies were satisfactory for histological interpretation (compared with 76% of 346 biopsies taken via a hydraulic multiple biopsy capsule from a separate group of patients). At least one biopsy was satisfactory from 87% of the patients. A previous study having shown that biopsies from this site are comparable to those from the conventional site at the duodenojejunal junction, it is concluded that endoscopic duodenal biopsy is a valid alternative to conventional suction biopsy and, moreover, has a number of advantages.