Silver‐coated polyvinyl alcohol (Ag/PVA) was prepared using 3,4‐dihydro‐3,6‐dimethyl‐1,3‐2H‐benzoxazine as a reducing agent reported in the petty patent of our research group. Ag/PVA22000 is applicable for making solutions and gels. Solutions of Ag/PVA22000 have exhibited antimicrobial properties against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans, while the gels inhibited only S. aureus, B. subtilis, E. coli, and P. aeruginosa. Therefore, the solutions and gels tend to be used in antimicrobial sprays and gel bandages. Moreover, Ag/PVA145000 was able to form hydrogels by gamma‐ray irradiation. Therefore, the hydrogels with the lowest amount of silver were prepared from 5.0 wt.% of Ag/PVA145000 at the 20 kGy of gamma‐ray irradiation. The results illustrated that the hydrogels exhibited antimicrobial properties against S. aureus, B. subtilis, E. coli, and P. aeruginosa. However, no inhibition of C. albicans was observed for any prepared hydrogels.