The hypothesis of METARICH Study is that it is possible to draw up a profile of the faecal microbiota, which could contribute in the future to the characterisation of certain chronic pathologies. The pathologies chosen for the study were selected because they are associated in the literature with changes in the faecal microbiota.

All the study data will be collected from the patients' clinical records and from the questionnaires set up (patient inclusion questionnaire and information questionnaire).

• The patient inclusion questionnaires collect the following variables: characteristics of the pathology (precise phenotyping by the clinician, assessment of severity, age, progression) as well as biological parameters obtained in the patient's usual check-ups and current treatments specific to the pathology.
• The patient information questionnaire collects information on lifestyle habits (smoking, alcohol, sporting activities, diet), stool sample data (Bristol scale, day and time of collection), treatment(s) received in the last 3 months and other chronic pathologies.

Inclusion Criteria:

List of patient inclusion criteria:

Male or female patient consulting the Rouen University Hospital for one of the 4 pathologies below:

• Obesity (with or without bulimic hyperphagia): BMI greater than 30
• Non-alcoholic steatohepatitis (NASH): Confirmation of the diagnosis of NASH by the clinician
• Colorectal cancer: Confirmation of the diagnosis of colorectal cancer by the clinician
• Parkinson's disease: Confirmation of the diagnosis of Parkinson's disease by the clinician

List of inclusion criteria for the control group:

• Adult patient aged less than 75 years.
• Ambulatory patient able to collect stools at home
• Patient who has read and understood the information letter and signed the consent form
• Patient affiliated to the social security system
• Aged between 18 and 75
• Affiliated with a social security scheme
• To the best of the volunteer's knowledge, free from the following pathologies: Obesity, hyperphagia, anorexia, bulimia, Crohn's disease, irritable bowel syndrome, haemorrhagic rectocolitis, NASH, steatosis, colorectal cancer, diabetes (type I and II), ankylosing spondylitis, rheumatoid arthritis, heart failure, atopic dermatitis, bronchopulmonary concer, Parkinson's disease and multiple sclerosis
• A person who has read and understood the information leaflet, signed the consent forms and is able to perform the stool collection.

Exclusion Criteria:

List of patient non-inclusion criteria :

• Patient under guardianship or incapable of giving consent
• Patient at the end of life or whose clinical condition is incompatible with stool collection
• Patient undergoing antibiotic therapy or who has received antibiotic therapy for less than 3 months
• Patient already included in a category 1 interventional clinical trial
• Patient already included in METARICH for another pathology
• Patient who has had a colonic lavage/emptying for less than 3 months

List of non-inclusion criteria for the control group:

• Person deprived of liberty by administrative or judicial decision or person subject to a legal adult protection measure, patient under court protection, patient under guardianship or curatorship,
• Person under antibiotic therapy or having received antibiotic therapy for less than 3 months
• Person already included in a category 1 interventional clinical trial.

60 patients with non-alcoholic steatohepatitis, 60 patients with colorectal cancer, 60 patients with Parkinson's disease, 80 patients 60 patients with obesity and 140 healthy volunteers will be selected.

The data provided will be the property of the sponsor and will be used solely for its own research activities.