Laser Nail Therapy - Cure Your Nail Fungus Today! br br (800) 672-0625 br br Your nails turning yellow might be your body’s way of saying that something is wrong. Your nails indicate changes in your health over time. Keep watching to find out the reasons why your nails turn yellow. br br You wear dark nail polish br Wearing nail polish can stain and turn your nails yellow. This is because of the dye in the nail polish that interacts with the keratin in nails. br br This can also get worse if you use nail polish remover that contains acetone. The acetone dissolves the nail polish and bonds it with you nail. br br Underlying health issue br Thyroid disease and diabetes may lead to yellowing of the nails. It is unclear why, but it may be due to high sugar levels and compromised immune system. br br Smoking br Smoking can also cause fingernails yellow due to the tobacco smoke. br br Fungal Nail Infection br When your nails are infected by fungus, it can turn your nails yellow. They may also be thickened and brittle.