Stuart's transport medium with a charcoal impregnated swab was tested for transport of biopsies from the gastric antrum for culture of Helicobacter pylori. Biopsies were cultured under microaerophilic conditions either within 2 h or after a delay of 24 h at 4 degrees C. In 65 patients referred for gastroscopy two biopsies were taken. Helicobacter pylori was found in 39 patients. The rate of survival of Helicobacter pylori was found to be as high in Stuart's transport medium after 24 h at 4 degrees C as in the paired biopsy which was cultured immediately after transportation in normal saline. In five (13%) of 39 patients positive for Helicobacter pylori, the organism was cultured from only one of the biopsies. It is therefore recommended that two biopsies be taken for culture.