Psyllium, a bulk-forming laxative, is used to treat constipation. It absorbs liquid in the intestines, swells, then forms bulky stool, which is then more easily passed. Interest in psyllium has arisen recently mainly due to its use in high-fiber breakfast cereals and from claims that high-fiber cereals containing psyllium are effective in reducing cholesterol levels. The US currently imports and consumes more than 8000 metric tons of psyllium annually.

The name psyllium refers to a subgenus of plants in the plantain genus (Plantago). These plants have very small seeds —a thousand seeds weigh less than two grams. The psyllium seed coat is the portion typically used, and although its main use has been as a laxative it is more appropriately termed a true dietary fiber.

Psyllium can cause side effects:

  • difficulty breathing
  • stomach pain
  • difficulty swallowing
  • skin rash
  • itching
  • upset stomach
  • vomiting

Popular brand names include:

  • Fiberall®
  • Hydrocil Instant®
  • Konsyl®
  • Metamucil®
  • Modane Bulk Powder®
  • Perdiem Fiber®
  • Serutan®
  • Siblan®