The primary objective of this study is to evaluate the safety and efficacy of collagen injection in patients with plantar fasciitis

This study is an open-trial study. Sixty subjects will be participated in it. The study will be explained to the subjects and they voluntarily agreed to participate in it. Their eligibility to participate in the study will be checked, and the patient will receive collagen or a placebo (normal saline) in the plantar facia through randomization. They will be asked to follow the guidelines of the investigators during the study and to visit the hospital seven times, including for screening and the date of re-injection. . At each visit, the subjects undergo a VAS, a clinical laboratory tests, and a physical exam to evaluate the safety and efficacy of Regenseal. (*Re-injection could be maximum 2times at visit2 and 3, one week apart based on the investigator's judgment after the initial injection. If the subject gets injection on the screening date, the total number of his or her visits will be six.)

Inclusion Criteria:

- 1. Patient with chronic plantar fasciitis (Patients who had been diagnosed with plantar fasciitis but had not been responsive to non-invasive treatment for more than three months (non-invasive treatments include drugs, physiotherapy shock wave, or stretching) 2. Patients who are able to complete the questionnaires related to the safety and efficacy of the study drug and who read and understood the guidelines 3. Patients who agreed to maintain the medication dose during the study period if they need to keep taking it. (Excluded anti-inflammatory analgesic drug for pain after the injection.) 4. Patients who agreed not to use physical therapy or shock wave during the study period.

5. Patients or their representative (for adults), or patients and their parent/guardian (for minors), who agreed to participate in the study and signed the informed consent form

Exclusion Criteria:

• 1. If patients or their families suffer from or have ever suffered from an autoimmune disease.

  2. Patients who have ever suffered an anaphylactic reaction. 3. Patients who have ever suffered hypersensitivity to an implant. 4. Patients with a history of allergy to porcine or bovine protein. 5. Patients with rheumatoid arthritis. 6. Patients with ankylosing spondylitis. 7. Patients who are suspected of having spinal deformity with a negative serum test 8. Subjects who are pregnant and/or breast-feeding and/or plan a pregnancy. 9. Subjects with psychiatric disorders who are considered inappropriate to participate in this trial by the Principal Investigator.