[4] Common causes include slow movement of stool within the colon, irritable bowel syndrome, and pelvic floor disorders.

[11] Constipation is more concerning when there is weight loss or anemia, blood is present in the stool, there is a history of inflammatory bowel disease or colon cancer in a person's family, or it is of new onset in someone who is older.

[15][16] However, people may have other complaints as well including:[3][17] The Rome III Criteria are a set of symptoms that help standardize the diagnosis of constipation in various age groups.

In children, causes can include diets low in fiber and fluids, underlying medical conditions, and reluctance to go to the bathroom.

[17][27] Certain calcium channel blockers such as nifedipine and verapamil can cause severe constipation due to dysfunction of motility in the rectosigmoid colon.

[29][30] Metabolic and endocrine problems which may lead to constipation include: pheochromocytoma, hypercalcemia, hypothyroidism, hyperparathyroidism, porphyria, chronic kidney disease, pan-hypopituitarism, diabetes mellitus, and cystic fibrosis.

[5][24][31] Constipation has a number of structural (mechanical, morphological, anatomical) causes, namely through creating space-occupying lesions within the colon that stop the passage of stool, such as colorectal cancer, strictures, rectocoles, anal sphincter damage or malformation and post-surgical changes.

[32] Constipation also has neurological causes, including anismus, descending perineum syndrome, desmosis and Hirschsprung's disease.

[33] Spinal cord lesions and neurological disorders such as Parkinson's disease and pelvic floor dysfunction[18] can also lead to constipation.

Bowel movements that are difficult to pass, very firm, or made up of small hard pellets (like those excreted by rabbits) qualify as constipation, even if they occur every day.

[15] Other symptoms related to constipation can include bloating, distension, abdominal pain, headaches, a feeling of fatigue and nervous exhaustion, or a sense of incomplete emptying.

Distinguish between acute (days to weeks) or chronic (months to years) onset of constipation because this information changes the differential diagnosis.

Low fiber intake, inadequate amounts of fluids, poor ambulation or immobility, or medications can contribute to constipation.

Rectal examination also gives information on the consistency of the stool, the presence of hemorrhoids, blood and whether any perineal irregularities are present including skin tags, fissures, anal warts.

[17][15] Abdominal X-rays are generally only performed if bowel obstruction is suspected, may reveal extensive impacted fecal matter in the colon, and may confirm or rule out other causes of similar symptoms.

[17] Colonic propagating pressure wave sequences (PSs) are responsible for discrete movements of the bowel contents and are vital for normal defecation.

Deficiencies in PS frequency, amplitude, and extent of propagation are all implicated in severe defecatory dysfunction (SDD).

[44] In chronic constipation of unknown cause, the main treatment involves the increased intake of water and fiber (either dietary or as supplements).

Side effects of fiber supplements include bloating, flatulence, diarrhea, and possible malabsorption of iron, calcium, and some medications.

[37] If laxatives are used, milk of magnesia or polyethylene glycol are recommended as first-line agents due to their low cost and safety.

Colectomy with ileorectal anastomosis is another intervention performed only in patients known to have a slow colonic transit time and in whom a defecation disorder has either been treated or is not present.

[3] Because this is a major operation, side effects can include considerable abdominal pain, small bowel obstruction, and post-surgical infections.

[37] Complications that can arise from constipation include hemorrhoids, anal fissures, rectal prolapse, and fecal impaction.

Severe cases ("fecal impaction" or malignant constipation) may exhibit symptoms of bowel obstruction (nausea, vomiting, tender abdomen) and encopresis, where soft stool from the small intestine bypasses the mass of impacted fecal matter in the colon.

[59] The reasons it occurs more frequently in the elderly is felt to be due to an increasing number of health problems as humans age and decreased physical activity.

[19] Since ancient times different societies have published medical opinions about how health care providers should respond to constipation in patients.

[61] After the advent of the germ theory of disease then the idea of "auto-intoxication" entered popular Western thought in a fresh way.

The majority of constipation cases are not tied to a medical disease, and treatment can be focused on simply relieving the symptoms.

[64] Constipation can cause discomfort for women, as they are still recovering from the delivery process especially if they have had a perineal tear or underwent an episiotomy.

Injury to those muscles by some of the above risk factors (examples- delivering a large child, lengthy second stage of labor, forceps delivery) can result in constipation.