Who should not take fiber supplements?

Fiber supplements should not be taken if you have narrowing of your esophagus or intestines, as there is risk of choking or obstruction. You should also not take supplements if you have trouble swallowing, due to the risk of choking. Do not use these products if you have an allergy to any of their ingredients. If you get the recommended daily intake of fiber through the foods you eat, then you do not need fiber supplements.

If you have certain conditions or take certain medications, you may be able to take fiber supplements but you need to be watchful of certain ingredients. In order to avoid possible interactions, it is a wise practice to discuss the use of fiber supplements with your doctor before you begin taking them. Diabetics should avoid supplements that contain sugar. Psyllium brands may contain salt, so avoid those if you are on a salt-restricted diet. People who have phenylketonuria must avoid brands that contain aspartame. Do not use supplements that contain polycarbophils if you use the drug tetracycline. People who use Coumadin must avoid supplements containing psyllium.
 

There are very few risks with taking fiber supplements in recommended doses. However, fiber supplements can affect the absorption of certain medications. Therefore if you are on medications, you should check with your doctor or pharmacist before starting a fiber supplement (or any new medication or supplement). Additionally, if not taken with adequate fluid intact, they may increase constipation rather than help relieve it.