Until recently, the culture of Helicobacter pylori in vitro has only been achievable with complex undefined media supplemented with blood products, such as Brain-heart infusion (BHI) medium, blood agar, chocolate agar, or lysed blood agar (1 ). Substrate utilization and metabolic activity during growth on these media is difficult to define; this has led to the use of techniques such as nuclear magnetic resonance (NMR) spectroscopy to investigate the metabolic pathways active in H. pylori (e.g., refs. 2–5). Defined media for the growth of H. pylori have now been described (6 ,7 ), however, and may facilitate future metabolic studies in this organism by more conventional techniques.