Insufficient dietary fibre is a common cause of constipation. An estimate of the fibre content of the diet can be gained by asking what would normally be eaten during a day, looking particularly for the presence of wholemeal cereals, brown bread, fresh fruit and vegetables. 

Changes in diet and lifestyle – for example, following a job change, loss of work, retirement
or travel. All may result in constipation. Stress or anxiety related to these changes can contribute. Inadequate intake of food and fluids, for example in someone who has been ill, may also be responsible for constipation. 

Lack of exercise or reduced mobility is also implicated and regular exercise has a role to play in managing constipation. People who are disabled may find it difficult to get to the toilet and lack of adequate privacy can also be a factor.

Inadequate fluid intake is another common cause of constipation. There is evidence that by increasing fluid intake in someone who is not well hydrated, the frequency of bowel actions is increased. It is particularly effective when it is increased alongside an increase in dietary fibre. This can be difficult for some people, such as the frail and elderly. Caffeine in coffee, tea and some soft drinks can aggravate constipation by contributing to dehydration. Alcohol can also cause dehydration.

Many drugs can induce constipation. The common culprits are opioids, such as the codeine in co-codamol and antidepressants (both tricyclics and SSRIs). Drugs with anticholinergic properties, such as oxybutynin, are also commonly associated with constipation. Some drugs for blood pressure such as diuretics and calcium channel blockers may also contribute to constipation. If prescribed drugs are thought to be contributing the patient should be advised to consult with their doctors’ surgery.

Previous history of the use of laxatives is relevant and is highlighted by the new MHRA restrictions. Continuous use, especially of stimulant laxatives, can result in a vicious cycle where the contents of the gut are expelled, causing a subsequent cessation of bowel actions for one or two days. This then leads to the false conclusion that constipation has recurred and more laxatives are taken. 

Chronic overuse of stimulant laxatives can result in loss of muscular activity in the bowel wall of the colon and rectum and damage to nerves responsible for stimulating peristalsis (an atonic colon) and thus further constipation.