Nails are brittle and easy to break may be caused by physiological factors, but also by malnutrition, nail fungus and other pathological factors. 1. Physiological factors: If the nails are exposed to detergents containing harsh chemicals for a long time, or if they often do manicure, it will cause the nails to become brittle and break easily. 2. Pathological causes (1) Malnutrition: Nails are mainly composed of protein, vitamins and trace elements, if the daily diet lacks these substances, it will lead to poor growth and development of nails, which will make the nails become easy to break. (2) Ringworm of the nails: commonly known as “gray nails”, usually caused by ringworm infection, manifested as thickening of the nails, cloudy, indicating unevenness, sensitivity and easy to crack, buckle or even fall off. If the nails become brittle and easy to break, on the basis of exclusion of physiological reasons, you need to go to the hospital in time, under the guidance of a professional doctor to standardize the treatment and medication, so as not to delay the condition.