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Glyset Side Effects

Generic name: miglitol

Medically reviewed by Last updated on Apr 1, 2022.

Note: This document contains side effect information about miglitol. Some of the dosage forms listed on this page may not apply to the brand name Glyset.


Common side effects of Glyset include: abdominal pain, diarrhea, gastrointestinal signs and symptoms, and flatulence. Other side effects include: decreased serum iron, and skin rash. See below for a comprehensive list of adverse effects.

For the Consumer

Applies to miglitol: oral tablet

Side effects not requiring immediate medical attention

Some side effects of miglitol (the active ingredient contained in Glyset) may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects.

Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More common

  • Bloated full feeling
  • excess air or gas in stomach or intestines
  • increase in bowel movements
  • loose stools
  • passing gas
  • soft stools
  • stomach or abdomen pain

Less common

For Healthcare Professionals

Applies to miglitol: oral tablet


The most commonly reported adverse reactions include gastrointestinal symptoms; they tend to diminish in frequency and intensity with time.


Very common (10% or more): Flatulence (41.5%), diarrhea (28.7%), abdominal pain (11.7%)

Postmarketing reports: Pneumatosis cystoides intestinalis (may present with symptoms of diarrhea, mucus discharge, rectal bleeding, and constipation), ileus (including paralytic ileus), subileus, gastrointestinal pain, nausea, abdominal distention.[Ref]

The severity of gastrointestinal symptoms may be decreased by dosage reduction and avoiding high gas-producing foods and sucrose. Some studies have demonstrated a decrease in the severity of gastrointestinal effects over time with continued administration.[Ref]


Common (1% to 10%): Skin rash[Ref]


Common (1% to 10%): Low serum iron[Ref]


1. "Product Information. Glyset (miglitol)." Bayer (2001):

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.