Although supplements such as Metamucil and Citrucel are generally marketed as laxatives, and are very useful for constipation sufferers, they can also be used to combat diarrhea because they add bulk to the diet and can make waste food more solid.
These supplements are not really medications - most are simply fiber products with no added drugs or herbs, and so they can be taken long term on a daily basis without worrying about side effects. They're just the equivalent of adding lots of fruit and bran to your diet, but without having to eat daily apples or worry about bloating from the bran.
Do check, though, that the supplement you choose is just made up of fiber and nothing more, as you will occasionally find one that has added chemical laxatives or other ingredients that can upset your stomach.
It is important to make sure you find the fiber supplement that's right for you, as IBS sufferers often have very sensitive stomachs. Some people find that the psyllium fiber in supplements such as Metamucil can irritate their intestines, so if that happens to you try one of the methylcellulose products such as Citrucel, or other types of fiber such as acacia fiber.
Another point to be aware of is that some manufacturers use artificial sweeteners in their products, and these can sometimes cause problems for IBS sufferers. There should be a normal, sweetener-free version to choose instead, and the amount of sugar in a few spoonfuls should not have a huge impact on any diet you are on.
Whatever type of fiber you choose, you must make sure to build the dosage up gradually. If you add masses of fiber to your diet all at once you will probably feel very gassy and bloated. Instead, try just a small spoon of fiber once a day and build up to the recommended dose on the label. Most supplements will recommend that you take the product with lots of water, and to make sure you are drinking enough water for the rest of the day as well.
It will take a little while before you see the effects of the supplement, so don't give up if you don't feel better after a few days. Try taking a supplement for one or two weeks to really give it time to work.
These days there are many different ways to take fiber supplements. You can buy the traditional powder form, which is swallowed with water or soft food, or you can buy wafers, tablets or capsules, which can be very handy if you need to travel and don't want to carry a whole can of fiber with you.
Most people prefer to take one dose of fiber in the early morning, perhaps with their breakfast, and then another with dinner or just before their evening meal.
You will need to experiment to find the right dosage for your symptoms and the best time to take the fiber, but if you can find a supplement and dose that works for you it will be well worth the effort, because you will have found a cheap, drug-free way to help keep your IBS under control.