My teeth are naturally yellow. can it be whiten naturally?

Dental: See a dentist and ask about bleaching or veneers- i don't know of any natural cures.

Teeth whitening: It depends. If your enamel is thin and your dentin is reflecting through, it cannot be naturally whitened. If however you have yellow staining, it can be treated by teeth whitening. Have a dentist evaluate you to see if you are a candidate for teeth whitening.

It can in a few : Appointments. See a dentist for professional teeth whitening without laser, followed by home whitening system with custom trays for the long term effect. Hope it helps.