How Fast Does Gas-X (Simethicone) Work?

It will begin to work within a few minutes.

Oct 04, 2018

Tracy asked

I have gastrointestinal issues and I was recommended to take Gas-X. How fast does it begin working?

At a glance

  • Simethicone works by breaking up and reduction the formation of gas bubbles.
  • It works quickly, within a few minutes of taking a dose.


Gas-X contains simethicone, an antiflatulent agent used for the symptomatic relief of flatulence (i.e. gas), gastric bloating, and postoperative gas pains.

Gas-X begins to work quickly after taking a dose by mouth, generally within a few minutes. This fast onset of action is due to how the medication works to relieve gas.

How Gas-X (Simethicone) Works

Simethicone is commonly referred to as an "anti-foaming" agent as it disperses and prevents the formation of mucus-surrounded gas pockets (i.e. bubbles) in the GI tract.

It does this by altering the surface tension of gas bubbles, preventing these pockets from forming and causing them to break apart more quickly. Simethicone allows for gas to be processed and eliminated in a more efficient manner.

As simethicone eliminates existing gas bubbles more quickly, it is sometimes used as an antifoaming agent in gastrointestinal and colonoscopy procedures

Gas-X (simethicone) is physiologically inert and is not systemically absorbed. Our bodies do not metabolize simethicone and it is excreted unchanged in the feces. Additionally, simethicone is not known to interfere with gastric secretion or nutrient absorption.

How To Take Gas-X

Gas-X is indicated to be taken up to 4 times per day after meals and at bedtime. Doses range from 40 mg to 180 per tablet (or similar dosage form).

High doses of simethicone are used for enhancing the delineation of upper abdominal anatomy in conjunction with ultrasound imaging. A specific product (SonoRx) is used for this purpose (3).

Final Words

Simethicone products, such as Gas-X, work very quickly after taking a dose by mouth and you should notice relief within a few minutes.

It is important to note that you may still experience flatulence and/or belching as gas is eliminated. It should noticeably decrease bloating, however.

  1. Simethicone in the treatment of infant colic: a randomized, placebo-controlled, multicenter trial. PubMed
  2. Evaluation of simethicone for the treatment of postoperative abdominal discomfort in infants. PubMed
  3. Simethicone Monograph. ClinicalKey (Subscription Required)

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