My grandfather’s remedy for constipation was an infusion of senna pods. Outside his house a senna bush bloomed throughout the summer every year. A thoughtful patient who had benefited from the senna on many occasions presented my father, when he married, with a small senna bush which flourished throughout my childhood and for many years thereafter, though I can’t recall him ever prescribing either senna pods or Senokot.

Constipation is not a disease but a symptom. Usually it is transient and results from nothing more serious than a change in lifestyle: dehydration caused by travelling, a change in exercise routine or too much food with too little fibre. Sometimes, however, constipation is a symptom — often an early one — of serious disease that needs urgent investigation and treatment.

Unfortunately, even the mention of constipation is subject to the taboos that affect anything related to the colon, rectum, anus and defecation. But, as a medical slogan once asked, why die of ignorance and embarrassment?

Too many people regard constipation as not having their bowels open every day — a Victorian concept as outdated as the senna bush outside the GP’s surgery. But doctors make a similar mistake in defining constipation as having a bowel movement fewer than three times a week. In fact, constipation means having a bowel movement less often than usual, with harder, frequently smaller, stools than usual; or having to strain.

The features of constipation may vary from patient to patient. It should never be assumed that everyone’s guts are the same, and that their bodily functions should conform to a pre-ordained concept of normality. Persistent constipation is a change in bowel habits from the patient’s usual pattern.

A quarter of the population suffer from constipation at some time. It is endured without complaint by the elderly, the pregnant, post-operative patients and others taking not only painkilling drugs but a host of other preparations. Yet it can also be a symptom of several neurological diseases including multiple sclerosis and Parkinson’s disease, and of untreated diabetes, irritable bowel syndrome, inflammatory bowel diseases and, of course, colo-rectal cancer. It may also be associated with anxiety and depression.

It is too little known that constipation can be the first sign of Parkinson’s disease and, unless treated, is liable to remain a problem for Parkinson’s patients for the duration of their illness.

Any change in bowel habits, or in the nature of a patient’s stools, needs explanation. Many a disaster has followed someone’s recourse to over-the-counter remedies without consulting a doctor in these circumstances. Once the cause has been determined, advice can be given and treatment prescribed that will prevent such common troubles as piles or, in the elderly, obstruction of the gut through faecal impaction.

The standard remedies, once diet and fluid intake have been adjusted and any special causes treated, is either a stimulant laxative (such as Grandfather’s senna); inorganic osmotics that draw more fluid into the gut (including magnesium salts or sodium sulphate, though in the long term these may upset the body’s biochemical balance); or organic osmotic or surfactant laxatives.

The organic osmotic laxatives are effective but may produce an unacceptable amount of wind. Surfactant laxatives are detergents that soften the stool. All the existing remedies are effective for a time and each has its own advantage that depends on the nature of the constipation, but sideeffects may prove a problem if they are used regularly. Chronic constipation needs medical supervision.

Recently Movicol (macrogol), a new class of laxative described as an isoosmotic, has been introduced. Movicol acts by delivering water to the large bowel so that the faeces are softer and bulkier. This increases stimulation of the nerves in the gut wall so the colon works more efficiently.

Movicol is not absorbed through the gut wall and into the blood; it merely acts by combining with the water that is taken with its sachet. It should help those who, despite attention to diet, exercise and all the other lifestyle factors, persist in having chronic constipation.