Twenty-one patients with 31 postoperative delayed open wounds resistant to conventional therapy were randomly allocated to three groups. Group 1 was treated with red low level narrow band (LLNB) light (660 nm); group 2 was treated with infrared LLNB light (940 nm); and group 3 was treated with a placebo such as the Biobeam machine (no light irradiation). Group 1 showed a significant improvement compared to groups 2 and 3 (t-test).