This book summarizes the challenges of Isolation of full length vacuolating cytotoxin A protein from gram negetive bacterium Helicobacter pylori by known molecular biology techniques.Use of cloning and western blotting techniques split this protein into two subunits: P33 and P55. Our understanding of the basic nature and properties of VacA need to be extended for proper isolation of this Cytotoxin protein molecule in complete form.