I recommend Jamsil Terhan Clinic.

The director and staff at Jamsil Terhan Clinic are all friendly and attentive. They provide thorough and attentive care. They're especially known for their chuna and herbal acupuncture, so keep that in mind. Someone I know received chuna and bone-strengthening therapy here, and it helped them achieve excellent bone alignment. They're also said they're great at posture correction, so if you live nearby, consider stopping by.