Evaluate the Efficacy and Safety of Goofice® (Elobixibat) in Patients With Chronic Constipation

Inclusion Criteria: \- At provisional enrollment 1. Men or women ≥ 20 years of age. 2. Include 2 or more of the following during the last 3 months with symptom onset of at least 6 months: 1. Straining during more than 25% of bowel movements (BMs);) 2. Lumpy or hard stools in 25% of BMs; 3. Sensation of incomplete evacuation in more than 25% of all BMs; 4. Sensation of anorectal blockage or obstruction in more than 25% of BMs; 5. Manual maneuvers required in more than 25% of BMs; 6. Fewer than 3 BMs per week. In addition to having at least 2 of the above criteria, the following must also apply: a. Loose stools are rarely present without the use of laxatives; b. Insufficient criteria for irritable bowel syndrome (IBS). 3. Ability to provide written consent. - At time of enrollment 4. A total of SBM frequencies \< 6 times during the 2-week screening period. Exclusion Criteria: * At provisional enrollment 1. Known or suspected allergy to components in elobixibat. 2. Known or suspected organic constipation. 3. Known or suspected symptomatic or drug-induced constipation. 4. Known or suspected slow colon transit type constipation. 5. Known or suspected excretory disorder constipation. 6. Currently have or history of gastrointestinal obstruction. 7. Currently have or history of abdominal hernia. 8. History of laparotomy other than simple appendectomy. 9. History of cholecystectomy or surgical or endoscopic intervention related to papillotomy. 10. Subjects in whom the dosage regimens of medications, of which changing the dosage regimens is prohibited, will be changed after the day of informed consent. 11. Cannot use the rescue medication (bisacodyl suppositories 10 mg). 12. Pregnant, lactating or potentially pregnant women, women who wish to become pregnant from the time of the informed consent to the last observation/test point, or women who do not agree to use appropriate birth control methods. The acceptable effective contraception methods include: a. Male or female sterilization, implant, or intrauterine device; b. Injectable, pill, patch, ring plus one barrier method\*; c. Two combined barrier methods\*. * Effective barrier methods are diaphragm, male or female condoms, sponge, or spermicides (creams or gels that contain a chemical to kill sperm). 13. Anemia, defined as hemoglobin ≤ 10 g/dL. 14. Concurrent serious renal disease (creatinine ≥ 2.00 mg/dL) or liver disease (total bilirubin ≥ 3.0 mg/dL, or aspartate aminotransferase(AST) or alanine transaminase(ALT) ≥ 100 U/L). 15. Concurrent clinical significant heart disease, including uncontrolled hypertension, arrhythmia, or heart failure. 16. History of serious drug-induced allergy needs emergent medical intervention, such as anaphylaxis, angioedema, generalized urticaria or bronchospasm. 17. Subjects have a history of cancer (other than basal cell or squamous cell carcinoma of the skin) unless the malignancy has been in a complete remission without maintenance chemotherapy for ≥ 5 years prior to the Screening visit. 18. Subjects who are taking part in another clinical study, or subjects who take part in another clinical study within 12 weeks prior to the day of informed consent. 19. Loss of weight greater than 5 kg one month before screening visit. 20. Determined by the investigator to be not suitable for the conduct of the study for any other reasons. 21. Subjects have a barium enema within 7 days of the Screening Visit. * At time of enrollment 22\. Subjects have a clinically significant finding on colonoscopy performed as required in accordance with the American Gastroenterological Association (AGA) guidelines (within AGA time frames). If polyps are found and biopsied, pathology must be reviewed and must be negative for cancer before the subject may be enrolled in the study. 23. Used the rescue medication (bisacodyl suppositories 10 mg) at least 6 times during the 2-week screening period or subjects who used the rescue medication at least 3 times in Week -1 of the screening period. 24. Used the rescue medication for less than 72 hours after bowel movement during the 2-week screening period. 25. Mushy stool or watery stool (Bristol Stool Form Scale type 6 or 7) in SBM during the 2-week screening period. 26. Used prohibited medications/therapies during the 2-week screening period