The scrotum side of the inner thigh a bag very hard, may be caused by a variety of reasons, common such as sebaceous cysts, folliculitis, etc., patients need to go to the hospital differential diagnosis, clear cause, give targeted treatment. 1, sebaceous cysts: often related to dominant genetic, common in adolescence, can occur in the head and face, buttocks, thighs and other places. The small cysts are hard and stick under the pores, while the large cysts are soft and adhere to the skin, with slow onset and occasionally fading on their own. If diagnosed, it can be removed by electrocoagulation, laser treatment or surgical excision; 2. Folliculitis: mainly seen in patients with low immunity, often caused by hair pulling, rubbing, scratching caused by skin breakdown, so that the pathogenic bacteria invade the hair follicles. If the patient has folliculitis in the scrotal area, the symptoms can be manifested as red papules, which can be accompanied by itching, redness and swelling of the surrounding skin, often with hard pockets. In extensive lesions, broad-spectrum antibiotic treatment such as cephalosporin, erythromycin, lincomycin, etc. should be given, while topical antiseptic drugs such as erythromycin ointment and mupirocin ointment can be used. Avoid local stimulation, eat a light diet, eat more vegetables and fruits, improve resistance and pay attention to personal hygiene; 3. Other: a bag on the inner thigh by the scrotum is very hard and may also be caused by enlarged lymph nodes caused by tumors, often adhering to the surrounding tissues, hard in texture, difficult to push, painless to touch, sometimes fusing with several enlarged lymph nodes to form a larger mass. It may be accompanied by fever, night sweats, emaciation, itching and other symptoms, and requires early treatment after examination at a hospital. In clinical practice, surgery is the main treatment method to remove the mass and cleanse the lymph nodes, and radiotherapy and chemotherapy are prescribed by the doctor.