So is it possible for someone to be constipated for a week, or even months?

Constipation associated with difficult or infrequent bowel movements certainly could last for a long time. However, with respect to an absence of bowel movements, this situation is unlikely to last for more than a week.

A person eating a regular diet every day could never go a month -- or even a few weeks -- without voiding several bowel movements. After only one week, this person would have abdominal pain, nausea, and possibly vomiting. Eventually, the vomiting would be of fecal material, and the person would be at risk of intestinal perforation. Both of these situations are dangerous, and require emergent treatment in a hospital setting.

It gets worse. Fecal material sitting in the colon for several days without moving is also dangerous. One adverse outcome is that the feces will irritate the colonic mucosa, eventually creating an ulcer that might perforate the colonic wall. This would lead to a catastrophic fecal peritonitis in the abdomen (with a high mortality rate). This is a stercoral ulcer, and is most commonly seen in elderly, bed-ridden nursing home patients who are typically constipated and may go several days without passing any feces.

So what about a person who is not eating any food? (For example, a hospitalized patient in ICU receiving nutrition via intravenous infusions.) Could this person go weeks to months without voiding stool? Most likely, this patient could go two to three weeks without voiding feces.

Why not longer? Keep in mind that even if we are not eating or drinking, our digestive system is still secreting fluids and mucous into the digestive tract. These fluids (gastric juice, bile, enzymes, mucous) will eventually pass through the alimentary tract and need to be excreted.

So my final thought is that it is nearly impossible for a person to go longer than a month without passing a bowel movement.

Why do I not completely rule out this possibility? The reason is that I have a deep respect for the resiliency and flexibility of the human body. Millions and millions of years of evolution and change have worked to provide each of us with a sophisticated and adaptable body. So even though I do believe that a month without a bowel movement is nearly impossible, I do keep the remote possibility open and attribute this to our wonderful and flexible anatomy and physiology.

Lastly, for any of you who may suffer from constipation, try to drink a lot of water every day. Aim for eight large glasses of water per day. Also, try to limit your intake of fat, and eat a lot of high-fiber foods. If the constipation still persists, a visit to your doctor is in order.

Best wishes,