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Most laxatives can be bought over the counter at your local chemists. They include bulking agents, osmotic laxatives, purgatives and stimulants and may be taken as tablets, medicines, enemas and suppositories.
Try a bulk laxative first with plenty of fluid and only if that doesn’t work should you move onto something stronger, but do ask your doctor or practice nurse to advise you on what is the best regime for you.


Bulking Agents

These are complex sugars or starches that cannot be digested in the small intestine. When they get to the colon, they tend to retain fluid in the bowel and nourish the generation of bacteria. This makes the colonic contents bulkier and softer, stimulating peristalsis and leading to an easier and more satisfying bowel movement. It is important to drink plenty of water with bulking agents. You should take this type of medication in the morning and the evening and be prepared to increase the dose if there is no effect. But remember it may take some days before you notice any change in your bowel action. Since bulking agents are fermented in the colon generating gas, you may well experience an increase in pain, bloating and wind when you first take them. This is usually quite mild and will get better as your bowel adapts.

placeholder Generic Name Brand Name
Bran Trifyba
Psyllium or Ispaghula husk Fybogel, Isogel, Ispagel, Metamucil,Regulan
Sterculia gum Methylcellulose Normacol Celevac


Osmotic laxatives

These are either solutions of sugars or sugar alcohols or salts that cannot be absorbed in the small intestine and retain water into the bowel, making faeces softer and easier to pass. It is important to drink more water when you are taking these laxatives as they can take water from the body. Since these substances are fermented by colonic bacteria, they may make symptoms of wind, bloating and pain worse and can cause anal irritation and soreness. These symptoms tend to clear as your bowel gets used to the medication.

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Lactulose Duphalac, Lacitol, Lactugal, Regulose



Purgatives also retain water in the bowel. They tend to be used to help clear impacted faeces, but if they are used regularly, they can deplete the body of salt and water. So only take these under your doctor’s supervision.

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Macrogol powder or polyethylene glycol plus salts Idrolax, Movicol, Laxoberel, Picolax
Macrogol powder or polyethylene glycol plus salts Citramag
Magnesium Sulphate Epsom Salts
Magnesium Hydroxide Milk of Magnesia, Andrews Liver Salts


Faecal softeners

These are useful if your stool are very hard. They lubricate and soften the stool and make it easier to pass. When oils are taken orally, especially to elderly people, there is a risk of aspiration into the lungs and pneumonia. The oil may also seep from the anus.

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Liquid Paraffin  
Sodium Docusate Dioctyl
Docusol Norgalax


Stimulant Laxatives

These act on the enteric nervous system to stimulate colonic peristalsis and secretion. They tend to be reserved for more resistant constipation and can cause people with the sensitive bowels of IBS to suffer more colicky abdominal pain. Stimulant laxatives are not generally recommended for IBS, but when constipation is particularly severe, people may find they are the only drugs that work. This may take several hours.

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Senna Manevac, Senakot
Bisocodyl Dulcolax


New Drugs

Prucalopride (Resolor) is a prokinetic agent that was introduced in 2010.  It acts on serotonin receptors to stimulate peristalsis and does not have the side effects of irritant laxatives.  It is licensed to treat severe laxative-resistant constipation in women. Prucalopride can only be obtained on prescription. For a recent review on Prucalopride, click link.

Lubiprostone (Amitiza) acts on chloride channel receptors to stimulate intestinal secretion and has been shown to be superior to placebo for people with severe chronic idiopathic constipation.  For a recent review, click link.

Linaclotide (Constella) was introduced in 2013 as a novel drug concept to treat constipation associated with bloating and abdominal pain.  It acts on intracellular machinery to stimulate secretion and persistalsis and it also has been shown to reduce intestinal sensitivity.  It is licensed for the treatment of IBS-constipation.  To see recent review on Linaclotide, click link

Brand new!  Elobixibat is an inhibitor of the bile acid transporter in the ileum.  It treats constipation by causing malabsorption of irritant bile acid, which stimulates the colon causing secretion and peristalsis  

placeholder Generic Name Brand Name
Lubiprostone Amatiza
Prucalopride Resolor
Linaclotide Constella

* only available on prescription



Bulk laxatives and irritant laxatives are sometimes marketed together as mixtures.

For example:

  • Manevac is a mixture of isphagula bark, plantago seeds and senna pods.

  • Senokot-S contains senna and psyllium.

  • Normacol plus contains sterculia gum plus stimulant Frangula bark.

Suppositories and enemas

Suppositories and enemas are useful when hard faeces tend to get stuck in the rectum and obstruct defaecation.

  • Glycerine suppositories retain water, soften the stool and stimulate a bowel action.

  • Carbalax contains sodium phosphate which draws fluid into the bowel by osmotic action.

  • Relaxit contains sodium citrate, sodium lauryl sulphate , sorbic acid, glycerol and sorbitol, a mix of osmotic laxatives and a detergent.

  • Dulcolax suppositories contain bisacodyl, which stimulates rectal peristalsis.

  • Micralax contains sodium citrate and sorbitol, which retain fluid in the bowel

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