I wonder if laxative medicines are able to soften pre-existing hard stool in colon or merely prevent them from being formed. I searched on the internet but found no helpful information. Sorry if the question is too basic.

I had encountered "stool softener" but found it somewhat ambiguous. After I wrote here, I noticed that the Wikipedia article uses "stool softener" only for emollient laxatives. It also states that "emollient agents prevent constipation rather than treating long-term constipation".

  • 1
    Welcome to MedicalSciences.SE! Please take the tour and read the help center. For reasons mentioned in this post and in How to Ask, we require prior research information when asking questions. See this list of helpful resources.
    – Carey Gregory
    Sep 9, 2019 at 23:07
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    Specifically, any reasonable effort at researching laxatives should have produced stool softeners, which do exactly what it sounds like they do.
    – Carey Gregory
    Sep 9, 2019 at 23:10
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    Carey Gregory, can I ask you to reconsider this. The OP said he was searching but found the issue ambiguous. Stool softener can help in preventing the formation of hard stool but not necessary in softening already formed hard stool. I consider it a valid and distinct medical question because it challenges the usual logic, which may not work here.
    – Jan
    Sep 10, 2019 at 15:06
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    @CareyGregory Is learning medicine for personal use off topic? Or is asking for medical prescriptions/advises off topic? Or both of them? Thanks.
    – apadana
    Sep 10, 2019 at 20:44
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    @apadana Asking for medical advice is off topic. So in this example asking how laxatives work is okay, but asking which ones would be best for you is not.
    – Carey Gregory
    Sep 10, 2019 at 21:20

1 Answer 1


Hard stool that stays in the colon for more than a couple of days is called "fecal impaction." Most medical sources recommend treating it with manually removing the stool (by a doctor, if necessary) and using rectally administrated enemas:

Softening of hardened stool and stimulation of evacuation with enemas and suppositories is often helpful...Most enema solutions contain water and an osmotic agent. One such combination contains water, docusate sodium syrup...and sorbitol... Rectally administered solutions mechanically soften the impacted stool and the additional volume gently stimulates the rectum to evacuate (Clinics in Colon and Rectal Surgery).

You can also check the "Fecal Impaction" part on Mayoclinicproceedings.org.

According to American Family Physician:

Fecal impaction should be treated with mineral oil or warm water enemas.

According to some studies, oral stool softeners may also help to remove hard stool (ScienceDirect).

Oral disimpaction can be accomplished by high doses of stimulant laxatives, docusate, mineral oil, and polyethylene glycol-electrolyte (PEG) solutions. Osmotic laxatives such as lactulose or sorbitol can be used in combination with other medication. Oral disimpaction is often associated with abdominal pain and colic, as well as an initial increase in fecal soiling.

The problem with oral softeners, stimulants and osmotic agents is that once you take them, you can't go back..They can cause severe bloating and abdominal or rectal pain, so one needs to judge carefully what to use. In fecal impaction, oral softeners can increase the amount of water in the intestine, but not necessary in the hard stool itself. This may cause pressure to push the hard stool out, which may not be successful and can be painful.

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