Thickened toenails may be physiological factors, but also may be the manifestation of certain diseases, such as congenital thick nails, psoriasis, lichen planus, nail fungal disease, etc., should be timely consultation to find out the cause of the disease. 1 physiological factors: human skin, nails, etc. with age and aging, fingernails or toenails can also be thickened with age, the elderly appear to toenail thickening is a normal physiological phenomenon. 2. Pathologic factors: (1) Congenital Thick Nail Disease: If there is thickening of toenails since childhood, it suggests congenital thick nail disease. (2) Psoriasis, lichen planus: patients with thickened toenails should carefully look for other diseases, such as psoriasis, lichen planus, etc., which can also manifest thickened toenails, blackened, cloudy, and so on. (3) Nail fungus disease: Nail fungus disease, also known as onychomycosis and gray nails, is a fungal infection of the nails caused by fungal infection of the nails and nail beds, and manifests itself as a gradual development of the edges to the inside, thickening, smudging, clouding, and brittleness. This symptom alone is not enough to diagnose the disease, and there may be other factors causing it. It is recommended that the patient consult a doctor in time to clarify the cause of the disease and give targeted treatment.