Nails that are brittle and easy to break may be deficient in trace elements such as calcium and zinc, and may also be related to diseases such as gray nails, lichen planus and psoriasis. 1. Lack of trace elements: When there is a lack of trace elements such as calcium and zinc, it tends to increase the brittleness of nails, so they break easily. 2. Gray Nail: It is a disease caused by ringworm infection. Because ringworm will destroy the structure of the nail plate, it will be manifested as thickened nails, easy to break and peeling off in clinic. 3. Lichen planus: it is a kind of skin-specific inflammatory reaction of unknown cause. When it involves the nails, it will lead to thinning and brittle nails, uneven surface of nails and so on. 4. Psoriasis Nail: It is the invasion of nails on the basis of psoriasis, causing abnormal changes in nail structure, such as the appearance of thimble-like pits in the nails, thinning, brittle, and easy to break. Nails are fragile and easy to break because there are many causes, the specific situation needs the doctor to carry out an interview to clarify the cause of the disease, and under the guidance of the doctor’s treatment.