Gray nail is a fungal infection that most commonly affects the toenails, followed by the fingernails. Toenail fungal infections are often primary, and fingernail fungal infections are usually due to scratching and other causes of inoculation infection. The nail fungus is mainly thickened, color change, brittle texture, clinical classification into various types: 1, superficial type, mainly for the surface of the nail uneven or white, topical drugs can have a good effect; 2, distal lateral type, manifested as the distal nail separation and color change, a long time will appear nail thickening, brittle texture; 3, serious for the whole nail destruction type, manifested as the entire nail lesions, and even nail loss, treatment is more. The treatment is tricky and often requires a combination of oral antifungal medication and topical medication. Toenail damage is most common in gray nails and is caused by poorly ventilated shoes or sweaty feet, so changing shoes and socks and keeping the feet dry can prevent toenail fungal infections. For the treatment of gray nails, it is difficult and easy to relapse due to the patient’s inability to use medication for a long time. The key to the treatment of gray nails is to achieve a course of treatment, regular review, and regular use of topical medication or oral medication if necessary, under the guidance of a doctor.