Laxatives should be used if you are passing harder, drier stools less often and dietary methods haven’t worked Laxatives work in five ways and any individual laxative may work in more than one way: there are laxatives which soften the motion such as lactulose, lubricate the motion such as liquid paraffin, increase the bulk of the motion such as fybogel, stimulate the bowel to contract to push the motions around the bowel such as senekot, or draw water into the bowel such as 'salts' like magnesium or aluminium hydroxide If you also have indigestion, it is a good idea to take magnesium hydroxide rather than aluminium hydroxide which tends to constipate the stool When you buy a laxative, ask your pharmacist how it works. The most gentle are lactulose and fybogel. Other laxatives are more powerful and may have side effects such as urgent diarrhoea All these medicines are very safe to take but it is always a good idea to discuss this with the pharmacist if you have any worries. The laxatives which stimulate or draw water into the bowel always work if you take enough of them! However in larger doses they can cause bowel spasms, colic and diarrhoea, which may be difficult to control particularly if you are older and can result in incontinence