Toenail faults are considered to have the following reasons: 1, due to vitamin or trace element deficiencies caused by toenail malnutrition, it is recommended that you can balance the nutrition from the daily diet, such as eating more vitamin-rich foods, but also can be used in a surgical way to remove the original toenail to allow it to grow again. 2, gray fingernails, you can go to the hospital to confirm the diagnosis, to do a fungal examination, if the diagnosis is gray fingernails can use Anti-fungal treatment, such as oral terbinafine hydrochloride or itraconazole capsules. 3, caused by calcium deficiency or endocrine disorders.