digestive system: constipation

The Classic Comprehensive Handbook of Cat Care


Constipation is the difficult or infrequent passage of feces. This sign does not occur often in healthy young cats, but is relatively frequent in sick and/or old ones. Although constipation may be caused by simple things such as improper diet or excessive hair ingestion during self-grooming, when a well-fed and well-cared-for young cat has recurrent bouts of constipation it is a reason to be concerned and may require diagnosis and treatment by a veterinarian.

Serious causes of constipation include rectal tumors, spinal cord dysfunction, and reduced colonic muscle function. Most normal adult cats have one or two bowel movements each day, but since each cat is an individual and diet has a great influence on stool frequency, you must learn your own cat’s daily routine. One day without passing a bowel movement is not normally a crisis situation, but any change in an individual cat’s normal bowel movement frequency, especially if accompanied by other signs such as straining to pass a stool, dehydration, sitting in a crouched or hunched-up position, loss of appetite, or vomiting warrants your investigation and possible veterinary evaluation.


If constipation is mild, a change in diet may relieve the problem. Canned foods containing large amounts of ground bone should be avoided; they can sometimes produce rock-hard stools only a veterinarian can remove. Feeding dry cat food will help some cats who tend to have trouble with mild constipation since dry products contain more bulk-forming fiber than canned foods. A meal of fresh liver is very laxative, and older cats who frequently do not drink enough to keep up with their obligatory water losses often benefit when extra water is added to their foods.


Commercial preparations containing psyllium fiber have been designed for humans to add bulk to the diet and hold water in the stool. These products are sold in health food and drugstores. They may be used to help treat recurrent mild constipation in cats. Give 1 to 3 teaspoonfuls (5 to 15 ml) mixed in the food once or twice a day. Bran is also an effective fiber laxative when mixed with a cat’s canned food. Use up to 4 tablespoons (120 ml) a day. Some cats accept canned pumpkin added to their diets (up to 4 tablespoons [120 ml per day]) more readily than psyllium fiber or bran, and it can also be an effective laxative. If you find that you must add bulk-forming preparations to your cat’s diet frequently, discuss the constipation problem with your veterinarian.


Mineral oil (1 teaspoonful per 10 pounds [1 ml/kg] body weight), white petrolatum (1 teaspoonful, [5 ml]) given orally, or docusate sodium or calcium capsules (DSS, dioctyl sodium sulfosuccinate, 50 to 100 mg orally) are all laxatives sold over the counter in drugstores that may be used to relieve more severe constipation. Infant glycerine or DSS suppositories for insertion into the rectum are also sold without prescription. These products work by softening and lubricating the stool.

Like all laxatives they should not be used on a continuous or frequently repeated basis without professional advice. Once or twice a day for two days should be sufficient to relieve simple constipation. Mineral oil interferes with the absorption of oil-soluble vitamins and prolonged continuous use can cause vitamin deficiency. Mineral oil should be administered in food. Do not attempt to give it orally; if inhaled, it can cause severe pneumonia. Stimulant laxatives such as those containing castor oil or bisacodyl are not recommended for home use without specific instructions from your veterinarian. Chronic use of such drugs can damage the bowel and actually aggravate the constipation problem.


An enema may be necessary to relieve impaction of the colon (hardened stool lodged in the lower bowel). This is best performed by a veterinarian who should give your cat a thorough physical examination before treatment. DSS-containing pediatric enemas can be purchased in drugstores if the services of a veterinarian are unavailable. To administer an enema, insert the lubricated nozzle into the rectum and administer the liquid slowly at a rate of 1 ounce per 10 pounds (about 1.5 ml/kg) body weight. Avoid enemas containing sodium phosphate. They are dangerous for cats and their use can cause death.


In long-haired cats, straining to defecate is occasionally associated with hair matted over the anus, not constipation. The cat sometimes cries, especially when making attempts to defecate. If you have a long-haired cat who makes repeated attempts to pass a bowel movement without success, be sure to examine his or her anus before concluding that the problem is internal constipation. Clip away any matted hair with scissors or clippers and wash the anus gently with an antiseptic shampoo. If the anus is very inflamed, a soothing antibiotic-steroid cream or ointment may help relieve discomfort. Prevent recurrent problems by keeping the hair around the anus clipped short.

Straining to eliminate associated with bladder problems and with severe diarrhea and intestinal inflammation is often confused with constipation. Be sure you know what the problem is before attempting to treat it.

Veterinarians must often perform rectal examinations by inserting a gloved and lubricated finger into the lower bowel to be certain a cat is constipated. In other cases × rays must be used for diagnosis.