diff --git a/ChangeLog b/ChangeLog
index 2e3b17a6dd..23d5855288 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Thu Feb  7 18:57:04 2008  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* string.c (rb_str_dup): reverted unneeded change.  [ruby-dev:33634]
+
 Thu Feb  7 16:33:51 2008  Tanaka Akira  <akr@fsij.org>
 
 	* io.c (io_reopen): don't change access mode for stdin, stdout and
diff --git a/string.c b/string.c
index 487a863912..a9e90f2848 100644
--- a/string.c
+++ b/string.c
@@ -564,7 +564,9 @@ static VALUE rb_str_replace(VALUE, VALUE);
 VALUE
 rb_str_dup(VALUE str)
 {
-    return rb_str_new3(str);
+    VALUE dup = str_alloc(rb_obj_class(str));
+    rb_str_replace(dup, str);
+    return dup;
 }