Sterrad® is commercial available from J&J in USA and J&J reported that Sterrad® has an ability to sterilize microorganisms by gas plasma. Gas plasma include reactive oxygen such as OH radicals. However, as shown in Figure 1 gas plasma exposed before and after hydrogen peroxide (H2O2) injection and sterilization, this means sterilization is done only by H2O2. In that sense, gas plasma did not contribute to sterilization, indicating inactivation is by only hydrogen peroxide, not by gas plasma. In addition, recently it was reported that Sterrad® can inactivate abnormal prion, but it is not true because prion is the most tolerable substance among targets of inactivation (Table 1). In that sense, hydrogen peroxide may contribute for disinfection, but not for sterilization and prion inactivation. The order of the toughness of inactivation is prion inactivation>sterilization>disinfection>preservation. The difference of sterilization and disinfection is whether it has the ability to destroy bacterial spores. Sterilization has an ability to destroy bacterial spores.