diff --git a/ChangeLog b/ChangeLog
index f73740842e..5592dfb261 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Tue May 14 03:21:42 2013  Koichi Sasada  <ko1@atdot.net>
+
+	* include/ruby/ruby.h: enable to generate write barrier protected
+	  objects (T_STRING).
+
 Tue May 14 03:19:59 2013  Koichi Sasada  <ko1@atdot.net>
 
 	* include/ruby/ruby.h: enable to generate write barrier protected
diff --git a/include/ruby/ruby.h b/include/ruby/ruby.h
index a46bf95b06..cbc7ad1a3c 100644
--- a/include/ruby/ruby.h
+++ b/include/ruby/ruby.h
@@ -689,7 +689,7 @@ VALUE rb_obj_setup(VALUE obj, VALUE klass, VALUE type);
 #define RGENGC_WB_PROTECTED_ARRAY 0
 #endif
 #ifndef RGENGC_WB_PROTECTED_STRING
-#define RGENGC_WB_PROTECTED_STRING 0
+#define RGENGC_WB_PROTECTED_STRING 1
 #endif
 #ifndef RGENGC_WB_PROTECTED_OBJECT
 #define RGENGC_WB_PROTECTED_OBJECT 1