The causes of cracked toenails include trauma, malnutrition and onychomycosis, and the treatments include general treatment, surgery and medication. 1. Trauma: If the cracked toenail is caused by trauma, if the cracking is not serious, it can be kept under observation, avoiding stress and contact with water, and waiting for the bruise to subside by itself; however, if it is very serious, or even separated from the nail bed, it is necessary to carry out surgery. 2. Nutritional deficiencies: When the body lacks calcium, zinc, vitamins and other nutrients, the growth of nails will be restricted and cracking may occur. You can supplement these nutrients from your diet by eating more fresh vegetables and fruits and drinking more milk. 3. Ringworm of the nails: commonly known as “gray nails”, caused by fungal invasion. Treatment is based on antifungal therapy, oral terbinafine or itraconazole. If you find cracked toenails, you need to go to the hospital in time to find out the specific cause of the targeted treatment.