In　this　paper,　we　consider　a　generalized　longest　common　subsequence　problem,　the　string-excluding　constrained　LCS　problem.　For　the　two　input　sequences　X　and　Y　of　lengths　n　and　m,　and　a　constraint　string　P　of　length　r,　the　problem　is　to　find　a　common　subsequence　Z　of　X　and　Y　excluding　P　as　a　substring　and　the　length　of　Z　is　maximized.　The　problem　and　its　solution　were　first　proposed　by　Chen　and　Chao　(2011)　[1],　but　we　found　that　their　algorithm　cannot　solve　the　problem　correctly.　A　new　dynamic　programming　solution　for　the　STR-EC-LCS　problem　is　then　presented　in　this　paper.　The　correctness　of　the　new　algorithm　is　proved.　The　time　complexity　of　the　new　algorithm　is　O　(nmr).　(C)　2013　Elsevier　B.V.　All　rights　reserved.