How often is Colon Hydrotherapy necessary? After your first session your colon therapist will be able to assess your needs based upon what is observed during the procedure, your dietary habit history, and your expectations and goals for cleansing and life style changes. Most people begin feeling better and removing large amounts of waste matter after 3 or 4 sessions. Many colon therapists recommend a series of 6 to 10 colonics over a period of weeks, for the first time client. Then, depending on the individual, a colonic every 3 to 6 months.