Diseases & Conditions



Constipation refers to delay or difficulty in passing stool or an increase in the hardness and size of stool. Constipation is the result of behavior or a lack of fluids and fiber in the diet. Hard or large stools can cause abdominal discomfort and can tear the anus. Increased fluid and fiber in the diet, behavior modification, and sometimes enemas and laxatives can help ease the discomfort.

Parents often worry about their child's bowel movements. However, most constipation has no serious consequences and should be a concern only when passing stools becomes painful and leads to further withholding of stools or when constipation causes other symptoms.

Stool frequency and consistency is variable throughout childhood, and there is no single frequency and type of stool that is “normal.” Newborn infants typically have four or more loose, yellow, and seedy stools per day. Breastfed infants typically have more stools than formula-fed infants and may defecate after each breastfeeding. After a month or two, some breastfed infants defecate less frequently, but the stools remain mushy or loose. After 1 year of age, most children have one to two stools a day that are soft and formed.

In older children, constipation is defined as the passing of hard stools that cause discomfort. It is most often caused by an insufficient amount of fiber in the diet. The condition also may be self-reinforcing, because discomfort while moving the bowels causes children to further withhold stool.

Constipation is extremely common among children. Although constipation rarely causes any serious severe problems, children who are defecating less than every other day, whose stools are hard or large, or who appear to have discomfort when defecating should be evaluated by a doctor. Chronic constipation can contribute to urinary problems such as urinary tract infections and bed wetting (enuresis).


The most common causes of constipation are dietary and behavior issues. Frequently, the child's diet contains insufficient amounts of fluid and fiber (such as from fruits, vegetables, and whole grains). Lack of fluid and fiber causes stool to become hard and difficult to pass. Such stools may cause abdominal discomfort, anal pain with defecation, or both. Also, passage of large hard stools may tear the anus (anal fissure), which is painful and may result in streaks of bright red blood on the outside of the stool or on the toilet paper. Because of these symptoms, or because the child does not want to take time to defecate, some children resist defecation (stool withholding behavior). As stool withholding behavior continues, constipation worsens, sometimes becoming a vicious circle. As a large amount of hard stool (fecal impaction) fills the rectum, it may enlarge, which can decrease the sensation of needing to defecate. Looser stool from above the hardened stool may then leak around this fecal mass into the child's underwear, which may cause parents to think the child has diarrhea when the actual problem is constipation.

Constipation that has existed since birth and constipation that does not go away after treatment suggest a physical defect, such as Hirschsprung disease (see Birth Defects: Hirschsprung's Disease ).


Mild constipation can be treated by increasing the amount of fiber in the child's diet and ensuring good hydration. If the child will not consume a high-fiber diet, a fiber supplement ( psyllium Some Trade Names METAMUCIL KONSYL ) can be given.

Behavior modification is also important. After eating a meal, the body has a reflex to pass stool. This is called the gastro-colic reflex. Frequently, a child ignores the signals from this reflex and puts off having a bowel movement. Putting off bowel movements contributes to the hardening of stool and subsequent constipation. Behavior modification techniques take advantage of this reflex. Having the child sit on the toilet for 5 to 10 minutes after meals helps retrain the digestive tract, develops a toilet routine, and encourages more regular defecation.

If constipation does not respond to diet and behavior modification, the doctor may recommend certain drugs that help soften stool and increase the spontaneous movement of the digestive tract. Such drugs include senna, magnesium hydroxide Some Trade Names MILK OF MAGNESIA , and polyethylene glycol.

Gentle enemas are an option for children who have a fecal impaction; however, they should be used only occasionally and under a doctor's direction.

Last full review/revision December 2007 by William J. Cochran, MD

Source: The Merck Manual Home Edition