Exploratory Evaluation of the Effect of Cholestyramine on Serum Levels of POPs in Obese Female Patients

Inclusion Criteria: * Female patients with a retained indication for bariatric surgery (BMI \> 40 kg/m2 or BMI \> 35 kg/m2 with complication(s) amenable to improvement by surgery) * Aged between 18 and 45 * Using effective contraception (oral contraception, hormonal or non-hormonal intrauterine device, progestin implant), which will be adapted in the perioperative period in accordance with current recommendations (HAS, BARIA-MAT) * Affiliated to a social security scheme * Have signed an informed consent form Exclusion Criteria: * Pregnant (urine pregnancy test) or breast-feeding women * Known allergy or intolerance to cholestyramine * Chronic constipation * Chronic pathology likely to interfere with treatment efficacy (unbalanced diabetes characterized by HbA1c \> 7%, known and treated dyslipidemia, chronic renal insufficiency with GFR \< 60 ml/min, hepatocellular insufficiency) * Patients receiving anti-vitamin K, digoxin or levothyroxine therapy, or likely to receive such therapy within 3 months of inclusion. * Phenylketonuria * Inability to give consent * Patient under legal protection (guardianship, curatorship, safeguard of justice...) * Patient deprived of liberty by judicial or administrative decision, * Patients under psychiatric care which makes it impossible for them to consent to participation, or who are hospitalized under duress. * Participation in another interventional study (outside the PaCO project).