Gray nail is a common disease caused by fungal infection, which usually results in discoloration, thickening, separation, and unevenness of the nails, and in severe cases, it can be followed by bacterial infection and cause onychomycosis. Trauma to the nail area or ringworm or tinea pedis, and not paying attention to hygiene, can easily cause gray nails, due to the stimulation of the nail area by pathogenic bacteria, which can lead to obvious abnormalities in the nail area, such as discoloration, thickening, separation, unevenness, detachment, buckling and so on. If gray nails are left untreated for a long period of time, they can become embedded in the skin, causing severe pain, and may lead to infectious diseases such as cellulitis and onychomycosis. Therefore, when the symptoms of gray nails appear, it is recommended to consult a doctor as soon as possible for examination and treatment to avoid aggravation of the disease.