Regexp match not working.. (SQL help)

I have a text column in a table, which I want to search through --
seeking the occurrence of about 300 small strings in it.

Let's say the table is like this:

    table1 (
         id   bigint primary key
        ,mytext   text
        ,mydate  timestamp without time zone
    );


I am using this SQL:

   SELECT id FROM table1
   WHERE   mytext   ~*   E'sub1|sub2|sub3|sub4...'
   LIMIT 10;

This is basically working, but some of the "mytext" columns being
returned that do not contain any of these substrings. Am I doing the
POSIX regexp wrongly? This same thing works when I try it in PHP with
preg_match. But not in Postgresql. I have tried several variations
too:

   WHERE   mytext   ~*   E'(sub1)(sub2)(sub3)(sub4)...'

 None of this is working. I cannot seem to get out the results that do
NOT contain any of those strings.

Appreciate any pointers!

Thanks!