Use the search bar to find a specific medication or choose the first letter in the sidebar on the right.


Generic Name

psyllium (SILL ee um)


Trade Name

Fiberall Powder, Wafer)
Metamucil(Powder, Wafer)
This product is available in an over-the-counter form.


What is psyllium?

Psyllium is a soluble fiber that comes from a plant most commonly grown in India. Although it is often labeled a laxative, it is not. Soluble fiber becomes gelatinous and sticky in water. It is not absorbed in the small bowel. It is broken down in the large bowel and becomes a food source for the bacteria that live in the colon. These healthy bacteria bulk up the stool, creating larger softer stool which is easier to pass. Other soluble fibers include oats, oat bran, fruit pectins, beans, and guar gum. Incidently, after psyllium is metabolized in the colon, some of it is absorbed and so adds some calories to the diet.


What is it used for?

Psyllium is a bulking agent that promotes bowel regularity. It can be used regularly, as opposed to harsh stimulant laxatives which should only be used occasionally. It is helpful in chronic constipation, irritable bowel syndrome, diverticulosis, hiatus hernia and diabetes. Soluble fiber may even lower cholesterol 10% to 15% if enough is taken.


How do I take it?

Follow your physician’s instructions carefully. Take each dose with a full glass of water. For new users, start by taking a small amount and then gradually increase to the recommended dosage to allow your system to adjust and to minimize gas and bloating. Store in a tightly sealed container away from moisture. Keep all medications away from children. Never share your medications with anyone else.


What do I do for a missed dose?

If you miss a dose of this medicine, take it as soon as possible. If it is almost time for your next dose, skip the missed dose and return to your regular schedule. Do not double up on this medication.


Are there interactions with food or beverages?

There are no known food or beverage interactions with psyllium. An increase in fluid intake, a diet rich in fiber or bran and regular exercise can improve bowel regularity.


Are there interactions with other drugs?

An interaction generally means that one drug may increase or decrease the effect of another drug. Also, the more medications a person takes, the more likely there will be a drug interaction. There are no known drug interactions with psyllium.


Is there a problem if I have another disorder or disease?

At times, a drug may have a different or enhanced effect when other diseases are present. At other times, the drug may worsen or effect another disease. Fiber should not be used if there is a suspicion of a chronic bowel obstruction unless discussed with the physician. It is also best to temporarily restrict fiber after abdominal surgery and when there is a flare-up of chronic bowel disorders such as Crohn’s disease and ulcerative colitis.


What about allergies?

People who have known allergies or asthma may be at an increased risk for a reaction from any new medication. The physician should always know a patient’s allergy history. Signs of an allergic reaction are skin rash, hives and itching. Of course, a person should not take psyllium if there has been a previous reaction to oral or inhaled psyllium powder, stool softeners or bulking agents.


What if I’m pregnant, considering pregnancy or breast-feeding?

Fiber is generally recommended during pregnancy when constipation can become a problem. Remember that fiber is not a laxative which is the term that the FDA makes manufacturers use on the label. Psyllium is no different than oatmeal or fruits which are always part of a healthy diet. These are all healthy soluble fiber.


What are the effects on sexual function?

There are no known adverse effects of psyllium on sexual function.


Are there other precautions?

  • The major side effect of all the soluble fibers, including psyllium, is the development of intestinal gas or flatus. It is the beneficial bacteria in the colon that create intestinal gases from certain food sources such as soluble fiber. So you may be limited in how much psyllium you can tolerate by this side effect. Insoluble fiber, found in wheat bran and cereals, does not have this side effect.
  • Always take psyllium with plenty of fluids. Insufficient fluid may cause the fiber to swell and cause choking or even rupture of the esophagus. Do not use psyllium if you have difficulty swallowing.
  • Contact your physician if constipation persists for more than a week with regular use of a bulk laxative or if rectal bleeding occurs.


How long is it safe to take psyllium?

Psyllium can be used safely long-term.


How about side effects?

Adverse reactions can occur with any drug, even over-the-counter medications. Some of these are mild such as a stomach upset, which may be avoided by taking the medication with food. Minor reactions may go away on their own but if they persist, contact the physician. For major reactions, the patient should contact the physician immediately.

For psyllium, the following are the observed side effects:


  • bloating
  • diarrhea
  • rumbling sounds
  • nausea
  • mild abdominal cramps


  • severe abdominal pain
  • vomiting
  • trouble swallowing


A physician’s comment…

Everyone should get a healthy amount of soluble and insoluble fiber in their food each day. There are many beneficial effects of fiber. It promotes bowel regularity and probably reduces the chance of heart disease and certain cancers. Psyllium should be viewed as nothing more than part of the foods you eat to stay healthy each day. There is a great deal known about fiber. For those who have diverticulosis, constipation or a hiatus hernia, link to the High Fiber Diet in the diet section.