Study on the Effect of Rhubarb Extract on Stool Frequency and Biological Markers of Intestinal Function in Seniors With Low Defecation

Inclusion Criteria: * presenting a number of stools ≥1 and ≤3 per week during the last month preceding the screening visit and during the last 15 days preceding the inclusion visit; * stools often (at least 25% of defecations according to the Rome III questionnaire) hard or lumpy, according to the bristol scale, at least the last 3 months over a period of 6 months; * not currently justifying, according to his attending physician, drug treatment; * Giving free and informed consent to the study in writing. Exclusion Criteria: Related to the patient: * subject with signs requiring further investigations: odynophagia, involuntary weight loss \>10% during the last 3 months before inclusion, persistent vomiting, hematemesis, blood in the stools, iron deficiency anemia, symptoms of obstruction, rectal bleeding, rectal prolapse …; * subject who has not been screened for colon cancer in the past two years; * subject participating in another therapeutic trial; * subject with a serious general pathology and in particular renal or hepatic insufficiency, cancer, chronic pancreatitis; * premenopausal women; * subject with known hypersensitivity to one of the constituents of the product under study; * subject who does not have the legal or ethical capacity to contract due to an impairment of his cognitive functions; * subject likely not to be compliant with the constraints imposed by the protocol; * subject not benefiting from a health insurance scheme. Related to the disorders assessed: * subject having taken in the 30 days preceding the screening visit or currently taking medication, food supplements and any food enriched or presented as containing substances, bacteria or yeasts likely to have an effect on the intestines and more particularly on intestinal transit, digestive comfort, gas production, the occurrence of abdominal pain. These products were also prohibited throughout the duration of the study; * subject following a particular diet (vegetarian, vegan, high protein, etc.); * subject on a low-calorie diet and monitored by a current or recent doctor or dietitian (\< 6 weeks); * subject undergoing medical treatment which, according to the investigator, could interfere with the evaluation of the study criteria: antibiotic, corticosteroid, anticholinergic, antidepressant, antiemetic, antihistamine, diuretic, calcium channel blocker, antiparkinsonian, antipsychotic, antacid, analgesic , NSAIDs, H2 receptor antagonist, hypnotic, sedative, iron supplement, opioid and narcotic, laxative, anti-diarrheal, anti-reflux; * subject with an alcohol consumption greater than 3 glasses of wine per day, or two pints of beer per day, or one glass of strong alcohol per day; * subject with a coffee consumption greater than 5 cups per day; * smoker; * subject with a BMI greater than 30; * subject with constipation attributable to an organic or anatomical cause (Hirschsprung's disease, hypothyroidism, mental deficiency, psychiatric illness, neurological abnormalities, history of colon or anus operation, colorectal cancer, anemia, etc.; * subject with a fiber intake higher than the recommended intake (more than 6 fruits and vegetables per day according to the PNNS questionnaire); * subject with severe constipation (less than 1 bowel movement per week during the 15 days preceding the inclusion visit); * subject with pelvic floor dysfunction; * subject with type 1 or 2 diabetes; * subject with a history of pathology or current disorder at the gastrointestinal level such as a duodenal ulcer, chronic colitis or a chronic inflammatory disease of the digestive tract (Crohn's disease, ulcerative colitis), celiac disease or the syndrome irritable bowel; * subject with a history of digestive tract surgery; * subject having undergone surgery in the two months preceding the study; * subject having undergone bariatric surgery; * subject with the practice of an intense sports activity (more than 10 hours per week of intense activity as defined by the WHO).