Kiwis and plain laxatives ease constipation, and the “lazy bowel” fear doesn’t hold up

Key takeaways

• In a trial in New Zealand, Japan and Italy, two peeled green kiwifruit a day added about 1.5 complete bowel movements a week for people with constipation, though the kiwifruit marketer Zespri helped pay for it¹².
• The 2023 U.S. gastroenterology guideline gave its strongest grade to polyethylene glycol (PEG) and to bisacodyl or sodium picosulfate for short-term or rescue use, and a milder grade to fiber, senna and magnesium oxide⁷.
• A 2005 review, summarized for patients by the nonprofit IFFGD, found no data that laxatives are habit forming, and people with spinal cord injuries who used bisacodyl for up to 34 years didn’t build tolerance¹¹.
• In a 2019 review, every randomized trial of bisacodyl-type stimulant laxatives lasted four weeks, so daily use for months hasn’t been tested¹².
• Iron pills, calcium or aluminum antacids, opioids and some blood pressure, seizure and depression medicines can cause constipation, so check your medicine list first⁵.

Between 2014 and 2017, researchers in New Zealand, Japan and Italy asked 184 people to try a simple swap². For four weeks, they ate two green kiwifruit a day with the skins removed. For another four weeks, they took 7.5 grams of psyllium, the fiber in many supplement powders¹². Both supplied about 6 grams of fiber¹.

In people with chronic constipation, the kiwifruit added about one and a half complete bowel movements a week¹². A “complete” movement is one that leaves you feeling fully emptied¹. In that group, psyllium added less than half as many¹.

There’s a catch worth knowing. Zespri, which markets New Zealand kiwifruit, partly paid for the trial, approved its design and employed two of the researchers². The New Zealand site also had a government grant². The volunteers’ symptoms were mild, and everyone knew what they were eating¹.

The result fits a bigger pattern. The best-tested fixes for constipation are ordinary: certain fruits, the right fiber and cheap over-the-counter laxatives used well. This guide rates each one and ends with a step-by-step plan.

Constipation is about how it feels, not just how often

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) defines constipation as fewer than three bowel movements a week, hard or lumpy stools, stools that are painful or hard to pass, or a feeling that you haven’t finished³. About 16 in 100 U.S. adults have symptoms, it says, and about 33 in 100 adults 60 and older³.

Researchers use a stricter test called the Rome IV criteria. You need at least two of six problems in at least a quarter of your bowel movements⁴:

• hard or lumpy stools;
• straining;
• a feeling of blockage;
• a feeling that you didn’t finish;
• needing your fingers to help;
• fewer than three movements a week.

Loose stools must be rare without a laxative. Symptoms must have started at least six months earlier, and they can’t fit irritable bowel syndrome (IBS)⁴.

By that yardstick, a 2020 survey of 5,931 adults in three countries found functional constipation in about 7.9% of Americans⁴. Across all three countries, women had it nearly twice as often as men, 10.1% versus 5.5%⁴.

One finding cuts against common belief. Across the survey, strict functional constipation was most common in adults 18 to 34, while NIDDK’s symptom figures point the other way³⁴. Part of the gap may be that the Rome system counts constipation from IBS or opioids separately⁴.

Either way, constipation isn’t only a problem of old age. Our gut motility article explains what counts as a normal rhythm.

Check your medicine cabinet before the laxative aisle

NIDDK lists medicines and supplements that can cause or worsen constipation⁵:

• iron supplements;
• antacids that contain aluminum or calcium;
• opioid pain medicines;
• calcium channel blockers, a type of blood pressure drug, and diuretics, or water pills;
• anticholinergic and antispasmodic drugs;
• anticonvulsants, used to prevent seizures;
• medicines for Parkinson’s disease;
• some antidepressants.

Opioids cause enough trouble to have their own diagnosis. In the 2020 survey, about 1.8% of U.S. adults met the criteria for opioid-induced constipation⁴.

Don’t simply stop the drug. NIDDK warns against changing or stopping any medicine or supplement without a health professional’s guidance⁶. Ask your prescriber or pharmacist whether a switch, a dose change or a planned laxative makes sense.

Two fruits have the strongest food evidence

Kiwifruit isn’t alone. Before the international trial, prunes were the only other single food shown to increase bowel movements, according to a 2023 review by Philip Schoenfeld, a gastroenterologist writing for the American College of Gastroenterology¹. He cites a 2011 trial comparing prunes with psyllium and a 2022 trial of prune juice against a placebo¹.

Prunes contain sorbitol, a sugar alcohol that pulls water into the bowel the way some laxatives do¹. That’s also the catch. Sorbitol is one of the fermentable carbohydrates called FODMAPs, so prunes can bring bloating and may worsen IBS¹.

Schoenfeld recommends both fruits for patients who dislike the texture of fiber supplements, with one caveat: prunes may add bloating¹. He also notes that many of his patients live in city “food deserts,” where kiwifruit can be hard to find¹.

How much? Lin Chang, a UCLA gastroenterologist and first author of the 2023 U.S. guideline, names five prunes or two kiwis a day as natural options for mild constipation⁷⁸. She puts their benefit roughly on par with fiber⁸.

The newest diet guideline comes from the British Dietetic Association. Published in 2025, it drew on four reviews covering 75 randomized trials, studies that assign people to treatments by chance⁹. Its statements covered kiwifruit, prunes, rye bread, mineral-rich water, fiber supplements, magnesium oxide, senna and probiotics⁹.

A clinical summary of the guideline puts the kiwifruit dose at two to three a day for at least four weeks, and rye bread at six to eight slices a day for at least three weeks¹⁰. That’s a lot of rye bread.

The guideline also made no recommendation for whole eating patterns, because there wasn’t enough evidence⁹. And most of its advice rests on modest data: of its 59 statements, only 8 drew on moderate-certainty evidence, and the rest on low or very low⁹.

If you’d rather start with food than with a pill, the research is on your side. The fair test is to pick one food, eat it daily and judge it after about four weeks, the length the trials used¹¹⁰.

The cheapest laxatives earned the strongest grades

In May 2023, the American Gastroenterological Association (AGA) and the American College of Gastroenterology (ACG) issued a joint guideline on medicines for chronic constipation⁷. The panel weighed trials, side effects, cost and what patients value, then made 10 recommendations⁷.

“Strong” means the panel recommends a treatment. “Conditional” means it only suggests one⁸. None of the treatments reached high-certainty evidence⁸.

Treatment	Grade	Certainty of evidence	What to know
PEG, an osmotic laxative such as Miralax6	Strong	Moderate	Best supported of the osmotic laxatives, which hold water in stool711
Bisacodyl or sodium picosulfate, stimulant laxatives	Strong	Moderate	For short-term use, meaning daily for up to four weeks, or as a rescue7
Fiber supplements	Conditional	Low	Only psyllium looked effective; data on bran and inulin were uncertain78
Senna, a stimulant laxative	Conditional	Low	Trials used higher doses than most people take; start low7
Magnesium oxide	Conditional	Very low	Avoid with kidney problems, because magnesium can build up7
Lactulose, a prescription osmotic	Conditional	Very low	Gas and bloating are common8
Linaclotide, plecanatide or prucalopride, by prescription	Strong	Moderate	For people who don’t respond to over-the-counter options7
Lubiprostone, by prescription	Conditional	Low	Same group7

Docusate, the stool softener in many medicine cabinets, got no recommendation. The panel named it, with fiber, lactulose and senna, among common treatments that still lack good data⁷.

NIDDK’s consumer advice, last reviewed in 2018, is more cautious than the newer guideline: it saves stimulant laxatives for severe constipation or when other treatments haven’t worked⁶.

Magnesium oxide doses in studies ran as high as 1,500 milligrams a day, and many people take 200 to 500⁸. Fiber is gentler when it starts small. Chang begins patients at about one rounded teaspoon of psyllium and works up to a rounded tablespoon, since jumping to 20 grams of fiber can be uncomfortable⁸. Fiber powders also need a full glass of fluid, as our article on water and digestion explains.

Skepticism should cut every way. Chang discloses advisory and consulting ties to several drug companies⁸. Yet in her panel’s guideline, the over-the-counter options PEG and bisacodyl earned grades as strong as the newer prescription drugs⁷.

Laxatives don’t wear out your bowel, but long-term tests are thin

Many people avoid laxatives for fear the bowel will get lazy and stop working on its own. A 2005 review in the American Journal of Gastroenterology checked that belief against the research and found little to back it¹¹. We read it through a summary from IFFGD, a patient-education nonprofit¹¹.

The reviewers found no data showing that people get hooked on laxatives or come to depend on them¹¹. Their most striking example involved people with spinal cord injuries who had used bisacodyl for as long as 34 years without signs of tolerance¹¹. Claims of colon damage came from uncontrolled studies, and the one controlled study found none¹¹. They judged harm unlikely at recommended doses¹¹.

NIDDK takes a practical line. If you’ve used laxatives for a long time and can’t go without one, it suggests working with your doctor to taper slowly, and says your colon should start moving stool normally again⁶.

Two cautions apply. First, heavy long-term overuse can drive blood potassium dangerously low¹¹.

Second, the trials are short. A 2019 Danish review found five randomized trials of bisacodyl or sodium picosulfate, with 1,008 patients, and each lasted four weeks¹². Between 78% and 99% of patients on the drugs rated them effective, compared with 46% to 54% on placebo, though mild side effects such as diarrhea and belly pain were common¹².

The authors said the evidence doesn’t support use beyond four weeks¹². The 2023 U.S. panel took a middle position, calling longer stimulant use “probably appropriate” but asking for more data on tolerance and side effects⁷. If you need a laxative most days, make a longer-term plan with a clinician.

A footstool is cheap, harmless and barely tested

Toilet footstools rest on a simple idea: sitting leaves a bend at the end of your bowel, and raising your feet may change that angle¹³.

In a test at Ohio State University’s Wexner Medical Center, healthy volunteers used a toilet stool for four weeks¹³. A 2017 conference poster from Ohio State, apparently on the same project, described internal medicine residents and their spouses; its figures point to about 52 people¹³. At the start, 44% said they strained significantly, 29% felt they didn’t empty completely, and 56% had seen blood on toilet paper in the past year¹³.

With the stool, 71% reported faster bowel movements and 90% reported less straining¹³. Two-thirds said they’d keep using it¹³. Before this study, which Ohio State’s Peter Stanich led, there was no medical evidence on whether such stools work, the medical center said¹³.

That’s one small study in healthy people, with no comparison group described, so it doesn’t show that a stool treats chronic constipation. Still, a stool costs little and carries almost no risk, and NIDDK suggests resting your feet on one for comfort⁶.

Children get constipated for different reasons

Constipation accounts for almost 1 in 20 children’s doctor visits, NIDDK says¹⁴. In children, the most common cause is holding it in¹⁴. A child may fear a painful bowel movement, feel stressed about potty training, dislike public bathrooms or not want to stop playing¹⁴. Held stool loses water and gets harder¹⁴.

The signs can be confusing. Besides fewer than two bowel movements a week, a child may clench or do an odd dance to hold it in, have wetting accidents or leak stool that looks like diarrhea¹⁴.

NIDDK’s home steps are more high-fiber foods and fluids, toilet time after meals, rewards for regular bathroom use and a pause in potty training until things improve¹⁴. Don’t give a child a laxative unless a doctor tells you to¹⁴. See a doctor if symptoms last more than two weeks, and right away for blood in the stool, bloating, constant belly pain, vomiting or weight loss¹⁴.

Your step-by-step constipation plan

This plan is our own, built from the guidelines and trials above. Move down a step only if the one before it hasn’t helped, and skip straight to a clinician if a warning sign appears.

Step	What to try	Give it	Evidence
1. Look for causes	Review medicines and supplements with a pharmacist; don’t stop prescriptions on your own56	A few days	Recognized causes5
2. Set a routine	Sit on the toilet 15 to 45 minutes after breakfast, go when you feel the urge, rest your feet on a stool6	Daily, ongoing	Not enough evidence for the stool13
3. Add one fruit	Two kiwifruit a day, or about five prunes if you don’t have IBS or bloating1810	About four weeks110	Promising but early
4. Add psyllium	Start with a rounded teaspoon in a full glass of fluid, building toward a rounded tablespoon8	About four weeks10	Promising but early
5. Add an osmotic laxative	PEG daily, or magnesium oxide if your kidneys are healthy, following the label78	Check with a clinician if you need it regularly	Strong for PEG7
6. Use a rescue laxative	Bisacodyl or senna for a stuck day or a short course78	Short-term, up to four weeks daily7	Strong for bisacodyl7
7. See a clinician	Prescription drugs, a check of the muscles that control bowel movements, and biofeedback to retrain them67	When steps 1 to 6 fall short	Strong for the prescription drugs7

What the evidence shows

Approach	What the research shows	Rating
PEG	Strong grade, moderate certainty, in the 2023 guideline7	Strong evidence
Bisacodyl or sodium picosulfate, up to four weeks	Strong grade; most rated them effective in four-week trials712	Strong evidence
Prescription linaclotide, plecanatide, prucalopride	Strong grade7	Strong evidence
Two kiwifruit a day	Trials in people with mild symptoms, partly industry funded12	Promising but early
Prunes or prune juice	Tested against psyllium and placebo; may cause bloating1	Promising but early
Psyllium	Conditional grade, low certainty; the one fiber that looked effective78	Promising but early
Senna or magnesium oxide	Conditional grades, low or very low certainty7	Promising but early
Rye bread or mineral-rich water	Recommended by British dietitians on low-certainty trials910	Promising but early
Toilet footstool	One uncontrolled study in healthy volunteers13	Not enough evidence
Docusate stool softener	Too little data for a recommendation7	Not enough evidence
Daily stimulant laxatives for many months	No trials longer than four weeks12	Not enough evidence
Laxatives make your bowel lazy or hooked	No supporting data; no tolerance after decades of bisacodyl11	Evidence says no, or unsafe

Natural-health traditions have long trusted prunes, fruit and a steady morning routine. The research largely backs that instinct, with numbers attached. It also suggests that a laxative, used thoughtfully, isn’t a betrayal of those values. It can be a short bridge while food and routine do their slower work.

Questions readers ask

The bottom line

Constipation is common at every age, and its best-tested fixes are simple. Start with your medicine list and a morning routine, then try kiwifruit or prunes for about four weeks, then psyllium. If you still need help, PEG and short courses of stimulant laxatives carry the strongest grades in the U.S. guideline.

Laxatives don’t make your bowel lazy, though no one has tested daily stimulant use for months. If you need one most days, or any warning sign shows up, bring it to a clinician.

Related reading

• How gut motility works, and why a cup of coffee can wake your colon like a meal
• Water helps your gut most with fiber and during a stomach bug
• Picking a fiber takes more than knowing soluble from insoluble
• Most Americans fall far short on fiber, and one swap a week closes the gap
• The preventive care that costs you nothing, and the exceptions

Sources

1. Schoenfeld P. “Two Green Kiwifruits Daily Improves Constipation” (review of Gearry R, et al., American Journal of Gastroenterology, 2023). Evidence-Based GI, American College of Gastroenterology, August 16, 2023. gi.org
2. Harrison L. “Kiwifruit Found Effective for Constipation.” MDedge, December 29, 2022. mdedge.com
3. National Institute of Diabetes and Digestive and Kidney Diseases. “Definition & Facts for Constipation.” NIH, last reviewed May 2018. niddk.nih.gov
4. Palsson OS, Whitehead W, Törnblom H, Sperber AD, Simren M. “Prevalence of Rome IV Functional Bowel Disorders Among Adults in the United States, Canada, and the United Kingdom.” Gastroenterology, 2020 (University of North Carolina repository). pubmed.ncbi.nlm.nih.gov
5. National Institute of Diabetes and Digestive and Kidney Diseases. “Symptoms & Causes of Constipation.” NIH, last reviewed May 2018. niddk.nih.gov
6. National Institute of Diabetes and Digestive and Kidney Diseases. “Treatment for Constipation.” NIH, last reviewed May 2018. niddk.nih.gov
7. Chang L, Chey WD, Imdad A, et al. “American Gastroenterological Association-American College of Gastroenterology Clinical Practice Guideline: Pharmacological Management of Chronic Idiopathic Constipation.” American Journal of Gastroenterology, 2023;118(6):936-954 (University of Minnesota abstract record), with recommendation grades as summarized by ACP Gastroenterology, May 26, 2023. experts.umn.edu and gastroenterology.acponline.org
8. “Highlights From the Joint AGA-ACG Guideline on Pharmacologic Management of Chronic Idiopathic Constipation” (interview with Lin Chang). Gastroenterology & Hepatology, November 2024. gastroenterologyandhepatology.net
9. Dimidi E, van der Schoot A, Barrett K, et al. “British Dietetic Association Guidelines for the Dietary Management of Chronic Constipation in Adults.” Journal of Human Nutrition and Dietetics, 2025;38(5):e70133 (abstract record). nutrition-evidence.com
10. GPnotebook. “Dietary and Lifestyle Advice in Management of Constipation” (summary of the British Dietetic Association guideline). Reviewed October 16, 2025. gpnotebook.com
11. Mandel KG. “Common Questions About Constipation: Myths and Misconceptions” (summary of Müller-Lissner SA, Kamm MA, Scarpignato C, Wald A, American Journal of Gastroenterology, 2005;100:232-242). International Foundation for Gastrointestinal Disorders, 2005. iffgd.org
12. Noergaard M, Andersen JT, Jimenez-Solem E, Christensen MB. “Long Term Treatment With Stimulant Laxatives: Clinical Evidence for Effectiveness and Safety?” Scandinavian Journal of Gastroenterology, 2019;54(1):27-34 (Capital Region of Denmark record). research.regionh.dk
13. Ohio State University Wexner Medical Center. “Toilet Stools May Make Going to the Bathroom Easier” (news release), January 9, 2019; and Modi RM. “Poster 83: Implementation of a Defecation Posture Modification Device.” ACG blog, October 2017. wexnermedical.osu.edu and gi.org
14. National Institute of Diabetes and Digestive and Kidney Diseases. “Constipation in Children” (Definition & Facts, Symptoms & Causes, Treatment). NIH, last reviewed May 2018. niddk.nih.gov
15. U.S. Preventive Services Task Force. “Colorectal Cancer: Screening.” Final recommendation statement, May 18, 2021. uspreventiveservicestaskforce.org