Gray nails are potentially contagious because they are caused by a fungal infection and the main site of involvement is the nail bed. After direct or indirect contact with patients with gray nails, it is possible to be infected with the fungus, especially when the resistance of the body is relatively low, it is easy to be infected, and thus the symptoms of onychomycosis will appear. Must pay attention to good protective measures, maintain personal cleanliness and hygiene, but also pay attention to wear shoes and socks with good ventilation, usually pay attention to regular work and rest, relaxation, strengthen nutritional support. Eat more vitamin-rich foods to help improve the body’s immunity. Avoid direct or indirect contact with patients with gray nails to help prevent gray nail infection.