diff --git a/Encode.pm b/Encode.pm
index aea404a..e4bf327 100644
--- a/Encode.pm
+++ b/Encode.pm
@@ -572,9 +572,10 @@ as a sequence of octets.  Because all possible characters in Perl have a
 
   $string = decode_utf8($octets [, CHECK]);
 
-Equivalent to C<$string = decode("utf8", $octets [, CHECK])>.
+Similar but not identical to C<$string = decode("utf8", $octets [, CHECK])>.
 The sequence of octets represented by $octets is decoded
 from UTF-8 into a sequence of logical characters.
+Returns unaltered $octets value if it already has UTF-8 flag on.
 Because not all sequences of octets are valid UTF-8,
 it is quite possible for this function to fail.
 For CHECK, see L</"Handling Malformed Data">.