• Begin by relieving faecal loading/impaction, if present.
• Set realistic expectations for the results of treatment of chronic constipation.
• Advise people about lifestyle measures — increasing dietary fibre (including the importance of regular meals), drinking an adequate fluid intake, and exercise.
• Laxatives are recommended:
• If lifestyle measures are insufficient, or whilst waiting for them to take effect.
• For people taking a constipating drug that cannot be stopped.
• For people with other secondary causes of constipation.
• As 'rescue' medicines for episodes of faecal loading.
• Start treatment with a bulk-forming laxative.
• It is important to maintain good hydration when taking bulk-forming laxatives. This may be difficult for some people (e.g. the frail or elderly).
• If stools remain hard, add or switch to an osmotic laxative.
• If stools are soft but the person still finds them difficult to pass or complains of inadequate emptying, add a stimulant laxative.
• Adjust the dose, choice, and combination of laxative according to symptoms, speed with which relief is required, response to treatment, and individual preference.
• The dose of laxative should be gradually titrated upwards (or downwards) to produce one or two soft, formed stools per day.

• For more information on the pros and cons of the various laxatives, see Advantages/disadvantages of laxatives

The recommended approach is largely based on expert opinion as there is limited evidence from clinical trials [Petticrew et al, 2001; American College of Gastroenterology Chronic Constipation Task Force, 2005; Hsieh, 2005; Longstreth et al, 2006; Ginsberg et al, 2007; Paré et al, 2007].

• Dehydration, reduced levels of physical activity, and low levels of dietary fibre are associated with constipation. However, the clinical impression is that increasing fluids above an adequate daily intake, increasing exercise, and advice to increase dietary fibre do not always relieve constipation.
• For all laxatives, trial evidence on efficacy and safety is limited. This is mainly because these agents have been in use for a long time, clinical trials were far less robust at the time they were originally licensed, and few new clinical trials have been done.
• For macrogols (products that are relatively new to the UK market), there is consistent evidence from four placebo-controlled trials that macrogols increase the frequency of bowel movements and relieve symptoms [Frizelle and Barclay, 2007]. There are also trials that compare macrogols with other laxatives [Frizelle and Barclay, 2007]. But, as all the trials used fixed doses, the evidence is of little relevance for approaches that adjust doses to the individual's needs.
• There is reasonable consensus between experts [Locke et al, 2000; Hsieh, 2005; Ginsberg et al, 2007; Paré et al, 2007] that for chronic functional constipation in adults:
• Bulk-forming laxatives are a good first-line choice.
• Osmotic and stimulant laxatives are reasonable second-line choices.