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!