diff --git a/ChangeLog b/ChangeLog
index 8358b855bf..d79fb3ed10 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+Sun Dec 27 18:08:15 2015  Kuniaki IGARASHI  <igaiga@gmail.com>
+
+	* string.c (rb_str_lstrip_bang, rb_str_rstrip_bang): [DOC] Fix
+	  ruby-doc comments for String#rstrip! and lstrip!.  It looks like
+	  dropped bang.  [Fix GH-1175]
+
 Sun Dec 27 15:14:20 2015  Eric Wong  <e@80x24.org>
 
 	* io.c (io_getpartial): remove unused kwarg from template
diff --git a/string.c b/string.c
index f4519ea425..cf9d1c7aac 100644
--- a/string.c
+++ b/string.c
@@ -7684,7 +7684,8 @@ lstrip_offset(VALUE str, const char *s, const char *e, rb_encoding *enc)
  *
  *  Refer to <code>strip</code> for the definition of whitespace.
  *
- *     "  hello  ".lstrip   #=> "hello  "
+ *     "  hello  ".lstrip!  #=> "hello  "
+ *     "hello  ".lstrip!    #=> nil
  *     "hello".lstrip!      #=> nil
  */
 
@@ -7773,7 +7774,8 @@ rstrip_offset(VALUE str, const char *s, const char *e, rb_encoding *enc)
  *
  *  Refer to <code>strip</code> for the definition of whitespace.
  *
- *     "  hello  ".rstrip   #=> "  hello"
+ *     "  hello  ".rstrip!  #=> "  hello"
+ *     "  hello".rstrip!    #=> nil
  *     "hello".rstrip!      #=> nil
  */