why he give wrong output

hello all
 i want to check the word begin with (for example)
"filter" ,but recipe give wrong output.
i use thecharacter which check at the begininig of the line.
:0:
* ^Subject:.*mail
/home/vpopmail/domains/virtual.example.com/rizvi/Maildir/.Trash/
but procamil send the mail to this folder either it is on the
first word or after a word.
like
mail control or control mail but i want to check it at begining
it can't work.
any help.thanks
wait for a good reply.