Enhanced degradation of chitosan by applying plasma treatment in combination with oxidizing agents for potential use as an anticancer agent.

•Plasma treatment in combination with H2O2 effectively reduced molecular weight of chitosan.•Plasma treatment not only reduced the use of H2O2 but also accomplished fast reaction rate.•By this method, chitosan (ca. 400kDa) was degraded to be water-soluble chitosan (≤6.5kDa).•Chitooligosaccharide (COS), up to 9-mers, was produced up to 40% of the degraded products.•The obtained COS had anticancer activity against cervix cancer cell line (HeLa cell).