If for some reason, you’d like to exclude some categories from searches, you have to tweak WordPress a bit because there’s no built-in solution to this problem. Happilly, here’s a code to do that job!

To achieve this recipe, replace the categories IDs on line 3 and paste the following code on your search.php template:

 <?php if( is_search() )  : $paged = (get_query_var('paged')) ? get_query_var('paged') : 1; query_posts("s=$s&paged;=$paged&cat;=1,2,3"); endif; ?> 

You’re done! See you tomorrow 😉