The dangers of gray nails mainly include destroying the nails, infecting other parts of the body, infecting other people and so on. 1. Destroying nails. Gray nail is due to nail infection caused by ringworm, due to the ringworm will cause damage to the nail bed, nail plate, so it will lead to nail thickening, discoloration, warping shells, and even nail fall off and so on. 2. Infection of other parts. Gray nail is a kind of infectious disease, can spread in itself, so it will be infected to other nails, even skin and other parts of the body, such as ringworm, jock itch and so on. 3. Infect other people. Gray nail can be infected through close contact or contact with the patient’s contaminated utensils, so the items used in daily life must pay attention to do exclusive use. Gray nail must be given timely standardized treatment and life care, reduce the harm.