Recently it has been demonstrated that chi-tosan is capable of adsorbing dissolved oxygen from the solution.This process plays an important role in iron ion sorption. The forcedoxygen dissolution in water is used in many technological pro-cesses. Since theinteraction of oxygen and water molecules proceeds through weakvan der Waals forces, thorough investigations of the role of dis-solved oxygen in chemical processes are few in numberThe ability of chitosan to adsorb the oxygen couldbe one of the reasons of its antimicrobial activity, which has notbeen discussed before. It is well known that oxic environmentsare hazardous to bacteria. The antimicrobial action of molecu-lar oxygen is explained by possibility to abstract electrons frommany redox enzymes with a continuous formation of an intracel-lular superoxide and hydrogen peroxide. The formed compoundscan destroy activities of metalloenzymes and the integrity of DNA.Remarkably, the action of well-known biocide silver is similar tothat of oxygen