Dulcolax vs. Colace: OTC Treatments for Constipation

Medically reviewed by Erika Prouty, PharmD

Dulcolax (bisacodyl) and Colace (docusate sodium) are over-the-counter (OTC) medications used to treat constipation. While both are helpful for relieving symptoms, these medications differ in how they work in the body.

Dulcolax is a stimulant laxative. It triggers the body to push stool out of the intestines. Colace works as a stool softener. It softens the hardened stool in the intestines by increasing the water content. This makes it easier to pass the stools.

This article will cover how each medication works, their key similarities and differences, side effects, and what to expect when taking them.

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Dulcolax vs. Colace: Key Differences and Similarities

Dulcolax is a stimulant laxative. It stimulates the intestines, causing the stool to move out of the intestines. Colace is a stool softener. It works by increasing the water content in your stool, making it easier to pass. These medications are recommended for occasional constipation.

Dulcolax and Colace can also be used for opioid-induced constipation (OIC). Opioids can cause the bowels to become too relaxed, preventing them from being able to push out stool.

Dulcolax comes in tablet and suppository forms. The tablets are taken by mouth, whereas the suppository is inserted rectally.

Colace comes in capsule and liquid formulations. It is also available as a rectal enema in its generic form, docusate.

How Long Do They Take to Work?

Dulcolax takes six to 12 hours before producing a bowel movement. It shouldn't be used for over a week without talking to your healthcare provider.

Continued use of Dulcolax can cause you to struggle to have bowel movements when you stop taking it.

Colace, on the other hand, may take 12 to 72 hours before producing a bowel movement. You should take it regularly for one to three days to get the full therapeutic effects of the medication. Therefore, it does not provide quick relief from constipation symptoms.

Side Effects of Dulcolax vs. Colace

As with most medications, Dulcolax and Colace have potential side effects. Talk to your healthcare provider if you have concerning reactions to using them.

Common side effects with Dulcolax can include:

  • Stomach pain or cramps

  • Diarrhea

  • Fainting

Severe side effects with Dulcolax may include rectal bleeding.

Common side effects with Colace may include:

  • Stomach cramps

  • Throat irritation

  • Nausea

Severe side effects with Colace may include:

  • Rash

  • Dyspnea (shortness of breath)

  • Hives

  • Vomiting

  • Fever

  • Stomach pain

Safety Warnings

When using Dulcolax or Colace, keep the following in mind:

  • Dulcolax tablets have an outer coating. It should be swallowed whole with a glass of water, as chewing or crushing the tablet will reduce its effectiveness in your body. If you cannot swallow without chewing, inform your healthcare provider for other ways to take it.

  • If you need to use Colace for more than one week, it is recommended to talk to your healthcare provider about additional options to help you treat constipation.

Stop taking these medications and contact your healthcare provider if you:

  • Fail to have a bowel movement after taking it

  • Have symptoms of nausea, stomach pain, and vomiting

  • Develop rectal bleeding

Is It Safe to Take Dulcolax or Colace While Pregnant?

Constipation is a common symptom of pregnancy. Oftentimes, OTC medications are needed for relief.

Dulcolax and Colace will not cross the placenta to affect the fetus if used during pregnancy. Therefore, they are generally considered safe to use while pregnant. However, Dulcolax use should be as limited as possible due to the risk of side effects such as electrolyte imbalances. It's typically recommended to use other products before Dulcolax in pregnancy.

Drug Interactions

Don't take Dulcolax within one hour of drinking milk or taking heartburn medications. This can cause the outer coating of the pills to dissolve too soon, reducing its effectiveness.

Some of these heartburn medications may include:

  • Antacids, such as Tums

  • H2 blockers, such as Pepcid AC (famotidine)

  • Proton pump inhibitors (PPIs), such as Protonix (pantoprazole) and Prilosec (omeprazole)

Colace should not be taken with mineral oil, as it can increase the absorption of mineral oil in the body, which can cause swelling.

Dulcolax vs. Colace: Which One Should I Choose?

Both medications are effective in relieving constipation. However, Dulcolax may begin working within a few hours, whereas Colace may take one to three days to see an improvement.

For this reason, you may opt for Dulcolax if you're looking for quick relief for your constipation symptoms. On the other hand, if you need a longer-term solution, Colace may be a better option.

It is important to discuss all health conditions and current medications with a healthcare provider when discussing which treatment is right for you.

How Does Dulcolax and Colace Compare to Miralax?

Certain studies have shown that Miralax can help alleviate constipation faster than other medications, including Dulcolax or Colace. Talk with your healthcare provider or pharmacist about what OTC options are best for your specific treatment of constipation.

Other OTC Treatments for Constipation

Dulcolax and Colace are only some of the options available to help treat constipation. Other treatments that are available over the counter include:

  • Senna (sennosides): Senna is a stimulant laxative like Dulcolax. It can help stimulate the intestines to push out stool.

  • Miralax (polyethylene glycol 3350): Miralax is what is known as an osmotic laxative, which allows more water to enter the intestine. This allows stool to pass more easily.

  • Magnesium citrate: Like Miralax, magnesium citrate is an osmotic laxative.

  • Metamucil (psyllium): Metamucil is known as a bulk laxative, meaning it can increase the size of your stool, which can help it pass through your intestines. Metamucil and other bulk laxatives are not recommended if your constipation is due to side effects from opioid use, as it can cause a dangerous blockage in your intestines.


Both Dulcolax and Colace are formulated to help reduce symptoms of constipation. However, their side effects, their time to take effect, and the types of dosage forms they come in differ. Dulcolax and Colace also work differently; Dulcolax is considered a stimulant laxative, while Colace is a stool softener.

If laxatives don't help your symptoms, or you experience frequent constipation, talk to a healthcare provider about other treatment options.

Read the original article on Verywell Health.