Only a few pharmacological studies have been carried out on men and guinea pigs to determine the gastric diffusion of antibiotics, which are active against Helicobacter pylori. The results of these studies have been analysed in considering the physicochemical nature, the mode of administration, the way of gastric diffusion (topic and/or systemic) and the pharmacological interactions. The correlation of these pharmacokinetic results with those obtained in clinical trials is difficult because of the heterogeneity of the pharmacological and pharmacodynamic data. The absence of a convenient and suitable animal or in vitro study model renders further standardized pharmacokinetic studies in infected man and at steady state necessary.