Patient description: The patient is a 60-year-old woman admitted to the stroke department with a recent history of a second course of intravenous antibiotics for aspiration pneumonia. She is febrile and complained of abdominal pain and diarrhea (bowel movements eight times in 3 hours, large volumes of greenish, liquid stool each time). The patient's abdomen is generally tender and distend with hyperactive bowel sounds. She is febrile (38.4°C), tachycardic (113/min) and hypotensive (80/40 mmHg). The stool samples must were positive for Clostridium difficile toxin.

Clinical trial eligibility criteria: eligible ages (years): 22.0-70.0,  Constipation Chronic Idiopathic Constipation Irritable Bowel Syndrome With Constipation Age 22-70 years old 2. BMI >18.5 and <35 kg/m2 3. Rome III for functional constipation or IBS-C 4. Continued IBS-C or CIC throughout Run-in period 5. Compliant with reporting during Run-in (confirm the presence of constipation during the 7-day Run-in baseline period; patients are required to report an average of <3 continuous spontaneous bowel movements [CSBMs] and ≤6 spontaneous bowel movements [SBMs] per week via the interactive web response system). 6. Ability to follow verbal and written instructions 7. Ability to record daily bowel habits, including frequency, stool consistency (BSFS), straining (EoPS), completeness of evacuation, and Patient Reported Outcomes (PROs) (abdominal discomfort, severity of constipation, bloating, overall relief) 8. Informed consent form signed by the subjects  History of loose stools 2. History of irritable bowel syndrome with diarrhea (IBS-D) or mixed irritable bowel syndrome (IBS-M) 3. Non-compliance with reporting during Run-in 4. Patients reporting laxative, enema, and/or suppository usage for >2 days or any usage of a prohibited medication during the Run-in period 5. Patients reporting watery stools for any SBM (Type 7 on the Bristol Stool Form Scale [BSFS]) or loose (mushy) stools for >1 SBM (Type 6 on the BSFS) in the absence of laxatives during Run-in 6. GI motility obstruction or GI tract structural abnormality 7. Current use of prescribed or illicit opioids 8. History of pelvic floor dysfunction 9. Need for manual maneuvers in order to achieve a BM 10. History of GI lumen surgery at any time or other GI or abdominal operations within 60 days prior to entry into the study 11. History of high-dose stimulative or cathartic laxative abuse as judged by investigator team 12. Neurological disorders, metabolic disorders, or other significant disease that would impair their ability to participate in the study 13. Cardiovascular disease, diabetes, cancer, Crohn's disease, ulcerative colitis 14. BMI of <18.5 or >35 kg/m2 15. Pregnancy (or positive serum or urine pregnancy test(s) in females of childbearing potential) or lactation 16. Absence of contraception in females of childbearing potential 17. History of allergic reaction to carboxymethylcellulose, citric acid, sodium stearyl fumarate, raw cane sugar, gelatin, or titanium dioxide 18. Administration of investigational products within 1 month prior to Screening Visit 19. of colonic inertia with symptoms of < 1 BM per 2 weeks 20. Subjects anticipating surgical intervention during the study 21. Known history of diabetes (type 1 or 2) 22. History of eating disorders including binge eating (except mild binge eater) 23. Supine SBP > 160 mm Hg and/or supine DBP > 95 mm Hg (mean of two consecutive readings) 24. Angina, coronary bypass, or myocardial infarction within 6 months prior to Screening Visit 25. History of swallowing disorders 26. Esophageal anatomic abnormalities (e.g., webs, diverticuli, rings) 27. History of gastric bypass or any other gastric surgery 28. History of small bowel resection (except if related to appendectomy) 29. History of gastric or duodenal ulcer 30. History of gastroparesis 31. History of abdominal radiation treatment 32. History of pancreatitis 33. History of intestinal stricture (e.g., Crohn's disease) 34. History of intestinal obstruction or subjects at high risk of intestinal obstruction including suspected small bowel adhesions 35. History of malabsorption 36. History of sucrose intolerance 37. History of hepatitis B or C 38. History of human immunodeficiency virus 39. History of cancer within the past 5 years (except adequately-treated localized basal cell skin cancer or in situ uterine cervical cancer) 40. Any other clinically significant disease interfering with the assessments of Gelesis100, according to the Investigator (e.g., disease requiring corrective treatment, potentially leading to study discontinuation) 41. HbA1c > 8.5% (> 69 mmol/mol) 42. Positive test for drugs in the urine 43. Any relevant biochemical abnormality interfering with the assessments of Gelesis100, according to the Investigator 44. Antidiabetic medications within 1 month prior to Screening Visit (except stable dose of metformin, ≤ 1500 mg/day, for at least 1 month in subjects with type 2 diabetes) 45. Medications requiring mandatory administration with meal at lunch or dinner 46. Anticipated requirement for use of prohibited concomitant medications 47. Implanted or externally worn medical device such as, but not limited to, a pacemaker, infusion pump, or insulin pump