Located in Otakanomori Nishi, Nagareyama City, Chiba Prefecture, Otakanomori Nishiguchi Clinic is a medical facility providing internal medicine-focused care. Currently, the clinic operates three days a week (Thursday, Friday, Saturday) on a completely appointment-only basis. Since June 2025, medical services have been expanded, with Dr. Aya Yamashita's internal medicine outpatient clinic newly added on Thursdays, accepting both new and follow-up visits like Friday and Saturday. In addition to general internal medicine, the clinic offers Nagareyama City stomach cancer screening, colorectal cancer screening, general gastrointestinal care, and insurance-covered examinations such as upper endoscopy and abdominal ultrasound. Endoscopic examinations are available via both oral and nasal routes, with emphasis on minimizing patient discomfort. Since June 2025, a head and neck surgery outpatient clinic (thyroid care) has also been established, with Dr. Yasuko Murakawa and Dr. Midori Wada in charge. Diagnosis, treatment, and follow-up for thyroid conditions including Graves' disease and Hashimoto's thyroiditis, as well as thyroid tumors, are provided, and nasopharyngoscopy and laryngofiberscopy examinations are conducted. Led by the director, a board-certified endocrine surgeon, the clinic has three doctors specializing in endocrine and thyroid surgery, with particular expertise in ultrasound diagnosis. The clinic is equipped to handle surgery for thyroid and parathyroid tumors and Graves' disease, and postoperative recurrent nerve paralysis care is addressed using swallowing endoscopy and esophageal contrast imaging. Facilities include parking and barrier-free accessibility. English is available as a service language, and completion of web-based medical history forms is required before consultation. The fever clinic accepts same-day telephone appointments only.