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Glyset Side Effects

Generic Name: miglitol

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

In Summary

Common side effects of Glyset include: abdominal pain, diarrhea, gastrointestinal 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

Minor Side Effects

Some of the side effects that can occur with miglitol (the active ingredient contained in Glyset) may not need medical attention. As your body adjusts to the medicine during treatment these side effects may go away. Your health care professional may also be able to tell you about ways to reduce or prevent some of these side effects. If any of the following side effects continue, are bothersome or if you have any questions about them, check with your health care professional:

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:
  • Skin rash

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, West Haven, CT.

Not all side effects for Glyset may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.

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