If the amount, color and quality of hair at the buttock groove are normal, this should be considered as anal hair, which can keep the anus ventilated and also has a certain role in keeping the anus warm, as bacteria can easily grow around the anus, and anal hair can reduce the probability of bacterial infection. If the amount of hair at the buttock groove is excessive, it is important to consider the possibility of local hirsutism, which is related to a variety of factors. First, consider a drug factor, such as topical minoxidil tincture or certain glucocorticoid creams, which can lead to an increase in localized body hair. Secondly, certain systemic diseases, such as adrenal gland diseases, including Cushing’s syndrome and adrenal tumors; such as ovarian system diseases, including polycystic ovary syndrome and ovarian tumors; such as endocrine system diseases, including hypothyroidism, insulin resistance syndrome and menopausal syndrome, can also lead to hairy buttock grooves.