Laxatives are foods or medicines that encourage bowel movement. Laxatives can be used to treat constipation or clear your bowels before a medical procedure.
Your GP or pharmacist may advise you to take laxatives if you have constipation. Constipation is when you have trouble opening your bowels. It’s a common problem, but can mean different things to different people, because bowel habits differ from person to person. However, health professionals define constipation in the following ways.
You may also be advised to take laxatives if you have a condition that could get worse if you strain during bowel movements, for example:
There are several types of laxative – some of which you can buy without a prescription. The main types are:
Each type of laxative works in a different way to help relieve or prevent constipation.
Laxatives are available as:
Sometimes, a laxative is given as an enema (liquid injected through a thin tube into your back passage). Enemas and suppositories work within minutes to clear your bowel.
Choosing the right type of laxative
Bulk-forming laxatives are usually recommended as the first type to try, especially if you find it difficult to get more natural fibre in your diet. Your doctor may also prescribe a bulk-forming laxative if you have a colostomy or ileostomy bag, irritable bowel syndrome, piles (haemorrhoids) or an anal fissure.
Bulk-forming laxatives usually come as powders or granules that you mix in water. It's important to drink enough fluids so that the extra bulk doesn’t build up in your bowel and cause a blockage. Bulk-forming laxatives may take two to three days to start working.
If a bulk-forming laxative doesn’t work or isn’t tolerated you may need an osmotic laxative. This too may take two to three days to start working. You must drink enough fluids while taking osmotic laxatives to avoid getting dehydrated.
Stimulant laxatives should only be used if other types of laxatives haven’t worked. They come as tablets, liquids, suppositories and enemas. Tablets and liquids work within six to 12 hours, so you should take them at night for an effect the next morning.
Faecal softener laxatives
Faecal softeners come as medicines taken by mouth, as well as suppositories or enemas. The enemas usually work faster.
Laxatives are usually only recommended for short-term use if changes to your diet, such as increasing your fibre and fluid intake, haven't worked. Taking laxatives over a long time can be harmful. It’s generally recommended that you stop taking laxatives once your bowel movements have returned to normal.
Sometimes you may need to take laxatives for weeks or months, especially if you have chronic constipation. However, you shouldn’t take laxatives for longer than a week unless your doctor advises you to. Also, you shouldn't give laxatives to children unless your doctor has prescribed them.
Always read the patient information leaflet that comes with your medicine, and if you have any questions, ask your pharmacist or doctor for advice.
Check with your GP or pharmacist before taking a laxative if:
This section doesn't include every possible side-effect of laxatives. Please read the patient information leaflet that comes with your medicine for more information. However, some common side-effects are listed below.
Check with your GP or pharmacist before you take any other medicines or herbal remedies at the same time as a laxative.
The main types of laxatives are shown in the table below.
All medicines have a generic name. Many medicines also have one or more brand names. Generic names are usually written in lower case, whereas brand names start with a capital letter.
There are many different products marketed for constipation. Some have more than one ingredient, or different ingredients sold under the same brand name. Ask your pharmacist for advice.
|Generic names||Examples of common brand names|
|ispaghula husk||Fibrelief, Fybogel, Isogel, Ispagel Orange, Regulan|
|sterculia||Normacol, Normacol Plus|
|lactulose||Duphalac, Lactugal, Laevolac|
|macrogols||Movicol, Movical-Half, Movicol-Paediatric|
|magnesium salts||Phillips Milk of Magnesia, Epsom Salts, Original Andrews Salts|
|phosphates||Fleet enema, Fletchers' Phosphate Enema|
|sodium citrate||Microlette, Micralax, Relaxit|
|co-danthrusate (with docusate sodium)||Normax|
|docusate sodium||Dioctyl, Docusol, Norgalax Micro-enema (enema)|
|sodium picosulfate||Dulcolax Pico Liquid, Dulcolax Pico Perles|
|Faecal softener laxatives|
|arachis oil||Arachis oil enema|
|liquid paraffin||Liquid paraffin oral emulsion|
Reviewed by Alice Rossiter, Bupa Health Information Team, February 2014.
For answers to frequently asked questions on this topic, see FAQs .
For sources and links to further information, see Resources .
This information was published by Bupa's Health Information Team and is based on reputable sources of medical evidence. It has been reviewed by appropriate medical or clinical professionals. Photos are only for illustrative purposes and do not reflect every presentation of a condition. The content is intended only for general information and does not replace the need for personal advice from a qualified health professional. For more details on how we produce our content and its sources, visit the about our health information page.