trouble getting values from forms

[adren]

I'm trying to build a guestbook. I use a form to get some informations (like name, email address and comments) from users and I store these informations in a DB whit a PHP script. The script doesn't work properly when I use some reserved chars like ' or " in form inputs.

Could you help me?
tnx

[Anon]

addslashes()
stripslashes()

[adren]

i've try to use
addslashes() and stripeslashes() but nothing is changed. when i type ' or " in input field of the form the script do not update the DB..