If you have been diagnosed with constipation your GP may prescribe a laxative as a first step alongside dietary and lifestyle advice. Laxatives are a type of medicine that help you pass stools. There are several different types and each one has a different effect on your digestive system.

Bulk-forming laxatives

Your GP will normally start you on a bulk-forming laxative. Bulking agents should always be taken with plenty of fluids as they absorb water and expand to fill the bowel with soft non-absorbable residue. This makes the stools softer, bulkier and easier to pass.

It will usually be two to three days before you notice the benefits of a bulk-forming laxative.

Osmotic laxatives

Osmotic laxatives are not absorbed by the body. They work by drawing fluid from the body into the gut, softening and increasing the bulk of the stool. They also promote the release of a natural enzyme which increases the movement of both the small and large intestine. These products can take up to 48 hours to act.

As with bulk-forming laxatives, make sure you drink enough fluids.

Stimulant laxatives

Stimulant laxatives stimulate the muscles that line your digestive tract and speed up the contractions of the muscles in the colon to reduce the time it takes for the passage of waste material through the bowel. They tend to work within 8-12 hours. They can be given either orally or rectally because they work directly on the gut wall.  Stimulant laxatives are often taken at night to produce an effect the following morning. If your stools are soft but you still have difficulty passing them, your GP may prescribe a stimulant laxative.

Laxatives that soften the stool should be taken regularly to ensure that the stool is always of the right consistency, while stimulant laxatives should be taken when you are planning to open your bowels only. A good diet which includes 5 portions of fruit and vegetables and two portions of fibre foods such as wholemeal bread or cereals can help to avoid the need for laxatives.

For more information on diet and fluid intake, please visit our Lifestyle, Fluids and Diet page.


There are a number of different suppositories available. Suppositories are placed directly into the back passage and prompt the bowel to want to empty usually within 20-40 minutes. They can be used to help relieve occasional constipation and they may also form part of a regular bowel management plan to prevent faecal incontinence.

In some cases regular laxatives and suppositories can be prescribed to people with neurological conditions and people with intractable constipation to help relieve constipation and faecal incontinence.

For more information on diet and fluid intake, please visit our Lifestyle, Fluids and Diet page.