Php imap_open

I have been tring to run a php script that calls imap_open( a user would send an email to a special mailbox and if the user was authorized it would be posted to the website.

here is the error

[lilac]$ lynx -dump

Fatal error: Call to undefined function: imap_open() in
/home/.foody/queer/ on line 39

Is this function disabled?