Drinking sufficient fluids and eating enough bulk-producer foods in the daily diet are imperative in preventing constipation and, in some serious cases, impaction. In addition to a high fiber diet, Metamucil® or other bulk producers may be useful. Stool softeners, such as docusate (Colace® or Pericolace®) or polyethylene glycol (MiraLAX®) may also be used on a daily basis without causing serious side effects or harm. Regular use of stimulant laxatives, such as Correctol® or Dulcolax®, should be avoided. Greater levels of activity and exercise, often difficult for polio survivors with significant physical disability, also aid bowel activity and stimulate the movement of fecal contents through the bowels. Persons with weak abdominal muscles may have more difficulty evacuating their bowels. Establishing a timing routine for bowel movements is also helpful in avoiding constipation. If it follows soon after a meal, it stimulates the gastro-colic reflex and can trigger colonic contraction.