How does senna work

It's often possible to relieve constipation without having to use laxatives. Before trying senna — or to stop constipation coming back — it may help to:. Page last reviewed: 24 January Next review due: 24 January Senna - Brand name: Senokot On this page About senna Key facts Who can and cannot take senna How and when to take it Side effects How to cope with side effects of senna Pregnancy and breastfeeding Cautions with other medicines Common questions about senna.

About senna Senna is a natural laxative made from the leaves and fruit of the senna plant. Senna comes as tablets and as a liquid that you swallow syrup. Help us improve our website Can you answer a quick question about your visit today? It's best to take senna at bedtime so it works overnight.

The most common side effects are stomach cramps and diarrhoea. These are usually mild and short-lived. Do not take senna for more than 1 week. Long-term use of senna can stop your bowel working properly on its own. Pee may turn a red-brown colour while you take senna.

This is harmless and returns to normal after treatment has finished. Senna is safe to take for most adults aged 18 years and over. Important Only give senna to children if a doctor or pharmacist recommends it. To make sure senna is safe for you, tell your doctor or pharmacist before starting senna if you: have ever had an allergic reaction to senna or any other medicine in the past have a bowel obstruction have Crohn's disease or ulcerative colitis have appendicitis are trying to get pregnant, already pregnant or breastfeeding.

Dosage The normal dose of senna tablets for constipation in: adults and children aged 12 years and over is 1 or 2 tablets at bedtime or 1 tablet of Senokot Max Strength children aged between 6 and 11 years is 1 single tablet at bedtime The normal dose of senna syrup for constipation in: adults and children aged 6 years and over is one or two 5ml spoonfuls at bedtime children aged 2 to 5 years only under medical supervision is half to one 5ml spoonful at bedtime Liquid senna comes with a plastic cup or spoon to measure the dose.

What if I forget to take it? What if I take too much? Taking an extra dose of senna is unlikely to harm you. If you're worried, talk to your doctor or a pharmacist. Common side effects Common side effects, which happen in more than 1 in people, are stomach cramps and diarrhoea. Serious side effects A very rare but serious side effect of senna is a severe raised, red, itchy skin rash on any part or all of your body.

Serious allergic reaction In rare cases, it's possible to have a serious allergic reaction anaphylaxis to senna. Information: You can report any suspected side effect using the Yellow Card safety scheme. Visit Yellow Card for further information. What to do about: diarrhoea — you may need to stop taking senna or reduce your dose.

Until the diarrhoea stops, drink lots of fluids, such as water or squash, to avoid dehydration. Signs of dehydration include peeing less than usual or having dark strong-smelling pee. Reducing your dose of senna may also help diarrhoea. Do not take any other medicines to treat diarrhoea without speaking to a pharmacist or doctor. It can help to eat and drink slowly and have smaller and more frequent meals. Putting a heat pad or covered hot water bottle on your stomach may also help.

It is available to buy from pharmacies. Senna works by stimulating the nerve endings in the walls of the large bowel colon and rectum. This makes the muscles in the bowel wall contract more often and with increased force, which moves the stools through the colon to the rectum so that the bowel can be emptied. Senna contains sennosides that are activated by the natural bacteria found in the colon, so it doesn't start working until it reaches this part of the gut.

If you don't have a bowel movement after three days of taking senna at bedtime you should consult your doctor. Laxatives should not be used on a continuous basis for longer than seven days without consulting your doctor. However, as with all medicines, you should get advice from your doctor before taking this medicine if you're pregnant. Other treatments of relieving constipation may be more suitable for you. This can cause kidney problems. Eating a healthy diet, drinking plenty of water and getting regular gentle exercise can all help prevent constipation.

Constipation is a common problem. It can mean either going to the toilet less often than usual to empty your bowels, or passing hard or painful stools. Constipation can be caused by a number of things. Not eating enough fibre or not drinking enough fluid can cause constipation. Some conditions such as pregnancy can cause constipation, as can a lack of exercise or movement such as being ill in bed and some medicines.

Often, increasing the amount of fibre in your diet such as by eating more fruit, vegetables, cereals, and wholemeal bread and drinking plenty of water each day can effectively prevent or relieve constipation. You could be recommended senna as a laxative to help relieve constipation if you cannot increase the fibre in your diet, or if this is insufficient. Senna works by encouraging the muscles in your bowel to move stools through your body.

This helps you to go to the toilet. It usually has an effect within hours. Senna normally causes a bowel movement within 6 to 12 hours, so it may be taken at bedtime to produce a bowel movement the next day. Do not take senna for more than 1 week without talking to your doctor.

Follow the directions on your package or prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand.

Take senna exactly as directed. Frequent or continued use of senna may make you dependent on laxatives and cause your bowels to lose their normal activity. If you do not have a regular bowel movement after taking senna, do not take any more medication and talk to your doctor.

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information. A regular diet and exercise program is important for regular bowel function. Eat a high-fiber diet and drink plenty of liquids eight glasses each day as recommended by your doctor.

This medication usually is taken as needed. If your doctor has told you to take senna regularly, take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule.

Do not take a double dose to make up for a missed one. Senna may cause other side effects.