Amoxicillin is one of the few products that can stain your teeth in no time. Even taking a single spoon of amoxicillin medicine can stain your teeth by turning their colors into yellow or orange. The best thing about amoxicillin stains on teeth is that they can easily be removed by brushing your teeth. If you take amoxicillin dosage on a daily basis, staining will stop once you quit taking medicine. The color will wipe off as they are not permanent.