Gray nails are somewhat contagious. Gray nails are caused by a fungal infection and may be contagious if you have close contact with other people. The main affected area of the nail is the nail bed. If you have direct or indirect contact with a person with gray nails, you may be infected with the fungus, especially if your body’s resistance is relatively low, and you may develop symptoms of onychomycosis. The first thing you need to do is to take care of your nails and avoid sharing your slippers with others. The most important thing is to pay attention to personal hygiene, wear breathable shoes and socks, and pay attention to nutritional support, eat more vitamin-rich vegetables and fruits to improve the body’s immunity and reduce the possibility of being infected with gray nails.