diff --git a/ChangeLog b/ChangeLog
index 191d597779..a99a27beb6 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Sun May 27 09:29:20 2012  Tadayoshi Funaba  <tadf@dotrb.org>
+
+	* ext/date/date_core.c: modified doc.
+
 Sat May 26 19:04:34 2012  Tadayoshi Funaba  <tadf@dotrb.org>
 
 	* ext/date/date_core.c: added description.
diff --git a/ext/date/date_core.c b/ext/date/date_core.c
index 3fc74af5fb..7dbf32158d 100644
--- a/ext/date/date_core.c
+++ b/ext/date/date_core.c
@@ -6927,12 +6927,11 @@ date_strftime_internal(int argc, VALUE *argv, VALUE self,
  *    0  use zeros for padding.
  *    ^  upcase the result string.
  *    #  change case.
- *    :  use colons for %z.
  *
  *  The minimum field width specifies the minimum width.
  *
- *  The modifier is "E" and "O".
- *  They are ignored.
+ *  The modifiers are "E", "O", ":", "::" and ":::".
+ *  "E" and "O" are ignored.  No effect to result currently.
  *
  *  Format directives:
  *