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Constipation Remedies That Actually Work (Graded by the Evidence)

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Medically reviewed by Dr. [PLACEHOLDER], MD · reviewedPLACEHOLDER reviewer

The best-proven options, graded honestly: PEG/Miralax (Grade A), and psyllium fiber or prunes (Grade B) [1]. Surprisingly, two kiwifruit a day is also Grade B — with the best tolerability of any option tested head-to-head [2]. Docusate, the classic "stool softener," has almost no modern evidence behind it [1][3]. Extra water only helps if you're actually dehydrated [4].

How were these actually graded?

The anchor source for this whole page is a 2021 systematic review of 41 randomized controlled trials that graded every major over-the-counter constipation option [1]. Grade A means good evidence from at least one well-designed placebo-controlled trial with a consistent effect. Grade B means positive trials exist, but with limitations — small sample size, no placebo arm, or mixed results. Grade I means the evidence is insufficient to grade at all. We’re using that same honest scale here rather than a marketing one.

The best-evidenced option: PEG (Miralax)

Polyethylene glycol (PEG) has “the most robust clinical evidence” of any OTC constipation therapy reviewed — Grade A, based on three placebo-controlled trials [1]. Pediatric long-term safety data is genuinely reassuring: multiple studies running a year or more of continuous PEG use found no electrolyte or biochemical abnormalities in children . If you’ve seen online concern about long-term neuropsychiatric side effects specifically, that concern traces to a parent-advocacy campaign that prompted a real FDA-funded investigation. The citable published study behind it is small — a 2018 study out of Nationwide Children’s Hospital found no link: it measured PEG’s glycol byproducts in the blood and urine of 9 treated children versus 18 controls, and levels stayed well below toxic thresholds with no sustained buildup compared to the untreated group [10]. That’s a reassuring result, not a definitive one — n=9 is a small sample for a single narrow question (were glycol levels building up in the body), not a large trial designed to rule out a behavior or mood link on its own. Reassurance here should rest on the whole body of peer-reviewed pediatric PEG trials, which consistently show a strong safety profile on the measures they tested — not on this one small study alone.

Whole-food options: kiwifruit and prunes

Two kiwifruit a day is Grade B evidence [1] — and in a head-to-head trial against psyllium and prunes, kiwifruit had a similar effect on bowel movements but the best tolerability of the three: significantly better bloating scores and the lowest patient dissatisfaction [2]. That combination — real evidence, whole food, essentially risk-free, and the easiest to tolerate — makes it a strong first thing to try before reaching for a supplement.

Prunes are also Grade B, and in a separate trial actually outperformed psyllium on stool frequency and consistency [5]. The tradeoff: prunes lost the tolerability comparison to kiwifruit, with more GI complaints and higher dissatisfaction in the three-way trial [2]. Read as: prunes for raw effectiveness, kiwifruit if your gut is sensitive.

Fiber: psyllium beats bran, and “gentle” fibers underperform

Psyllium (the fiber in products like Metamucil) is Grade B — “modest efficacy,” though it underperforms PEG, lactulose, and prunes head-to-head [1]. It clearly beats insoluble wheat bran for actually softening stool, because it holds water in the stool matrix rather than just adding bulk.

Here’s the honest surprise: inulin and other “gentle,” prebiotic-marketed fibers (common in gut-health gummies) have Grade I — insufficient evidence [1]. They’re also more fermentable, which is a big part of why they’re more associated with gas and bloating. “Gentler” is a marketing claim, not an evidence-based one, on the constipation question specifically.

The one everyone buys that barely has evidence: docusate

Docusate sodium — the classic drugstore “stool softener” — is Grade I, insufficient evidence. The review’s own words: “despite docusate’s frequent use… there is little clinical evidence to support its use,” and no new qualifying studies had been published since 2004 as of the 2021 review [1]. In a head-to-head trial, plain psyllium fiber actually beat docusate outright [3]. This isn’t a safety warning — docusate is low-risk — it’s an honesty flag: one of the most-purchased laxatives in the US just hasn’t been shown to do much.

Stimulant laxatives (senna, bisacodyl) are Grade A for effectiveness, with a real tolerability cost — a majority of trial participants on senna needed a lower dose due to abdominal pain or diarrhea. If you’ve heard senna “damages” the colon long-term: a 554-person case-control study found no increased colorectal cancer or polyp risk associated with long-term anthraquinone laxative use, even with visible pigment changes in the colon lining [6].

What about water, coffee, and squatting?

Water only meaningfully helps if you’re actually dehydrated, or if you’re adding fiber at the same time (fiber needs water to work) [4] — see our deep dive on water and constipation for the full nuance. Coffee measurably stimulates colon activity, but hasn’t been tested as a formal constipation treatment — see our coffee and your gut explainer. Squatting or a footstool is free and harmless to try, and may ease the subjective feeling of straining, but the foundational study behind the trend was small (28 people) and not a modern clinical-outcomes trial [8] — and squatting posture measurably raises blood pressure by about 8 mmHg, worth knowing if you have cardiovascular disease or hemorrhoids [9].

When to actually worry

Self-care is reasonable for occasional constipation without other symptoms. See a doctor if you haven’t had a bowel movement in over a week despite trying the above, if you’re using a stimulant laxative continuously for more than two weeks without reassessing, or if constipation comes with blood in your stool, severe pain, vomiting, or unintentional weight loss

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If a whole-food option or PEG gets you back to normal, that’s the evidence-backed path — you don’t need to keep shopping for a “better” fix. For everything else about frequency, see how often should you actually poop, or take the quick wizard for a personalized read.

References

  1. [1] Rao SSC, Brenner DM. Efficacy and Safety of Over-the-Counter Therapies for Chronic Constipation: An Updated Systematic Review. Am J Gastroenterol. 2021;116(6):1156-1181.
  2. [2] Chey SW, et al. Exploratory Comparative Effectiveness Trial of Green Kiwifruit, Psyllium, or Prunes in US Patients With Chronic Constipation. Am J Gastroenterol. 2021. PMID 34074830.
  3. [3] McRorie JW, et al. Psyllium is superior to docusate sodium for treatment of chronic constipation. Aliment Pharmacol Ther. 1998.
  4. [4] Arnaud MJ. Mild dehydration: a risk factor of constipation? Eur J Clin Nutr. 2003;57(Suppl 2):S88-95.
  5. [5] Attaluri A, et al. Randomized clinical trial: dried plums (prunes) versus psyllium for constipation. Aliment Pharmacol Ther. 2011.
  6. [6] Nusko G, et al. Anthranoid laxative use is not a risk factor for colorectal neoplasia: results of a prospective case control study. Gut. 2000.
  7. [7] MacMillan TE, et al. Docusate: use and evidence commentary. Am J Med. 2016.
  8. [8] Sikirov D. Comparison of straining during defecation in three positions: results and implications for human health. Dig Dis Sci. 2003.
  9. [9] Chakrabarti A, et al. Squatting posture and blood pressure findings. J Assoc Physicians India. 2002.
  10. [10] Williams KC, et al. J Pediatr. 2018. PMID 29395181. Nationwide Children's Hospital study (n=9 treated children vs. 18 controls) measuring blood/urine glycol levels in children on PEG 3350 — the citable published study behind the FDA-prompted neuropsychiatric-safety question (often mis-attributed to CHOP).