Christina Milian Gets Unwanted Bonus

Sources close to Christina tell TMZ ... she was out to dinner at Mexicali restaurant in Studio City ... and halfway through her salad, she felt a weird, chewy substance in her mouth.

Christina spit it out, and looked in horror as she eyed a giant wad of chewed gum. She then made a beeline for the bathroom and threw up.

We're told the restaurant comped her meal. But Christina is still freaked out about what happened, and filed a complaint with the L.A. Department of Health.

TMZ spoke with a rep for the Dept., who confirmed a complaint was indeed filed.

Christina tells TMZ, she's lookin' for a lawyer, but says, "The most important thing to me is to make sure my health is okay. Ever since the incident I have not eaten out."