addslashes() and binary data

A curious man is me. I have some binary data that I wish to insert into a database, and all examples I have seen have used: $to_save = addslashes($binary_data); This is supposed to escape all the characters that databases don't like. This function does not always work. Some times it is fine, other times it causes my SQL statement to be completely wrong, or it evaluates the ('$to_save') variable as NULL and returns SQL COUNT field incorrect. Am I missing something? Can someone tell me how they guarantee that all the bad characters will be escaped? Thanks in advance RDB