This protocol provides an easy and rapid method to prepare lipopolysaccharide from the gastric pathogen Helicobacter pylori for visualization on acrylamide gels by silver staining and for detecting the presence of Lewis antigens by Western blot. The silver staining is a four-step procedure, involving a 20 min-oxidation step, a 10 min-silver staining step, a 2-10 min color development step and finally a 1-min color termination step. Lipopolysaccharide from H. pylori wild-type and corresponding mutants analyzed by this method are described in a recent publication (Li et al., 2017). This crude preparation of LPS for silver staining is also applicable in other Gram-negative bacteria.