Two Low Volume Regimens for Colorectal Cancer Screening Colonoscopy

Inclusion Criteria: * Men and women aged 50 to 69 years who have participated in the early detection programme for colon and rectal cancer (PDPCCR) in Barcelona, who have obtained a positive result in the faecal occult blood test (≥20 μg Hb/g faeces) and who are scheduled for a screening colonoscopy at Hospital Clínic de Barcelona. Exclusion Criteria: * People who do not agree to participate in the study. * People with known severe renal failure (grade IV or V) and grade III and IV heart failure according to the New York Heart Association (NYHA) Scale of Functional Assessment of Heart Failure * Individuals who have undergone a colonoscopy in the past year. * Subjects meeting the Rome IV Criteria for the diagnosis of functional constipation * Subjects with mental disabilities or with a severe mental disorder (schizophrenia and other psychotic disorders, recurrent severe major depressive disorders, severe obsessive-compulsive disorder, severe personality disorders and bipolar disorders). * Individuals who do not understand Catalan or Spanish verbally and in writing. * Individuals with partial or total colon resection. * Individuals with a personal history of CRC or colorectal disease amenable to specific follow-up (ulcerative colitis, Crohn's disease, or colorectal adenomas). * Individuals with terminal illness or severe illness/disability that contraindicates further study of the colon. * People with gastrointestinal disorders that contraindicate the use of the study products (gastric emptying disorders, perforation or gastrointestinal obstruction, ileus, toxic megacolon). * People with congestive heart failure * Hypermagnesemia * Rhabdomyolysis * Phenylketourine * Glucose-6-phosphate dehydrogenase deficiency * People with hypersensitivity to the active ingredients of excipients * People with severe renal impairment