Can an Enlarged Prostate Cause Constipation? Why the Link Mostly Runs the Other Way

By Alice Hess
Published October 30, 2026 · Reading time about 10 minutes

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Most pages answer only half of this question: "can the prostate cause constipation?" The more useful half is the reverse, because it is the part you can act on this week. Constipation is a known cause of trouble emptying the bladder, several common medicines cause both problems at once, and the advice for one can quietly make the other worse.

Can an enlarged prostate cause constipation?

Not as a recognized symptom. The NIDDK's list of benign prostatic hyperplasia (BPH) symptoms is entirely urinary: trouble starting or emptying, a weak or interrupted stream, dribbling, waking at night to urinate, urgency, frequency and pain during urination. Its list of BPH complications (urinary retention, blood in the urine, urinary tract infections, kidney disease and bladder stones) does not include constipation either.¹ We found no NIH or American Urological Association source that names constipation as a symptom of an enlarged prostate.

So if constipation and urinary trouble started together, it is more likely that they share a cause, or that the bowel is affecting the bladder, than that the prostate is blocking the bowel. Our guide to enlarged prostate symptoms lists what BPH does cause.

How common is it to have both?

Very common, simply because both rise with age. The NIDDK estimates that about 33 of every 100 adults aged 60 and older have symptoms of constipation, and it names older adults, people who eat little fiber and people who take certain medicines or supplements as more likely to be affected.⁴ On the urinary side, the previous AUA guideline cites Olmsted County data in which moderate to severe urinary symptoms reach nearly 50 percent of men by their seventies.⁶ Put those together and many men in their sixties and seventies will have both problems at once, with or without any link between them.

That is why the order matters when you talk to your doctor. Which came first? Did either one change after a new medicine, a change in diet or less activity? The NIDDK defines constipation as fewer than three bowel movements a week, hard or lumpy stools, stools that are hard to pass, or a feeling that not all stool has passed, and adds that only you know what is normal for you.⁴ Write your own pattern down before the visit.

Can constipation cause urinary problems?

Yes, and this is well documented. The NIDDK lists constipation alongside an enlarged prostate, urethral scarring and urinary stones among the problems that can narrow or block the flow of urine and cause urinary retention.² Retention is the bladder not emptying fully, which can feel like the need to go again right after you finish, frequent small trips, a slow stream or trouble starting.²

For a man whose prostate already narrows the outlet, constipation adds a second possible blockage on top of the first. That helps explain why constipation can make a weak stream or a bladder that does not empty completely noticeably worse, even when the prostate has not changed.

The study that tested it: treating constipation improved urination

A prospective study from Tel Aviv followed 52 patients aged 65 to 89 who had both chronic constipation and urinary symptoms. Their constipation was treated, and they were checked monthly for 4 months, with an ultrasound of the bladder at the start and at the end.³

The authors concluded that relieving constipation "significantly improves LUTS in the elderly."³ Two honest limits: there was no comparison group, so some improvement might have happened anyway, and the abstract does not report how many of the patients were men. Still, few interventions for urinary symptoms are this cheap or this safe to try.

A larger Dutch study points the same way. It followed 417 men (average age 63) and 566 women from the community for two years. In men, each one-point rise in a constipation score over the first year went with a 0.376-point rise in urinary symptom scores. The authors call the associations weak, and an observational study cannot show which came first.⁷

Medicines that cause both constipation and urinary trouble

This is the connection that most pages on this topic miss. Put the NIDDK's list of medicines that can worsen constipation next to its list of medicines that can cause urinary retention, and several groups appear on both:^5,2

Two practical notes. First, some bladder medicines for urgency are themselves anticholinergics. The previous AUA guideline (2021, amended 2023) reports that constipation was more common when an anticholinergic (solifenacin) was combined with tamsulosin, and in one comparison constipation occurred in 5 percent of men on a fesoterodine combination versus 2 percent on a mirabegron combination.⁶ Second, the NIDDK says diuretics can make BPH symptoms worse, and it also lists them as a cause of constipation.^1,5

If both problems started or worsened after a new prescription, tell your doctor or pharmacist. The NIDDK is clear: "Don't change or stop any medicine or supplement without talking with a health care professional."⁸ For cold, allergy and sleep products, which affect the bladder, see cold and allergy medicine with an enlarged prostate.

The fluid trap: drinking less at night vs drinking enough for the bowel

Men with prostate symptoms are told to drink less, and people with constipation are told to drink more. Both pieces of advice come from the same NIH institute, and they fit together once you read them closely:

• For BPH, the NIDDK suggests drinking fewer liquids, "particularly before you go out in public or go to bed."¹
• For constipation, it says to drink water and other liquids to help fiber work better and to avoid dehydration.⁹

The answer is timing, not cutting. Drink most of your fluids in the morning and early afternoon, and taper in the evening. A man who simply drinks less all day to avoid night trips can end up constipated, and the constipation can then make the bladder empty less well. Our page on how many times a night is normal to urinate shows how to plan the evening, and drinks for an enlarged prostate covers what to drink.

What helps both

The AUA's 2026 guideline says "behavioral and lifestyle interventions should be explored before or alongside pharmacologic treatment."¹⁰ Its previous version listed avoiding constipation among those measures, together with limiting fluids before bedtime or travel, cutting back on caffeine and alcohol, more physical activity, weight loss and double voiding.⁶ From the NIDDK's constipation advice:^8,9

• Fiber: adults should get 22 to 34 grams a day depending on age and sex. Add it gradually. Good sources include whole grains, oatmeal, beans and lentils, berries, apples with the skin, pears, broccoli, carrots and nuts.
• Fluids: enough water to let the fiber work, front-loaded earlier in the day.
• Movement: regular physical activity may help relieve constipation.
• Bowel training: try for a bowel movement at the same time each day, for example 15 to 45 minutes after breakfast, because eating helps the colon move stool.
• Posture: relax your muscles or put your feet on a footstool.
• Laxatives: only as your health care professional advises, and stimulant laxatives only if constipation is severe or other treatments have not worked.

The NIDDK also suggests limiting foods with little to no fiber, such as chips, fast food, meat and processed foods like hot dogs.⁹ For the prostate side of the menu, see foods to avoid with an enlarged prostate.

Constipation and frequent urination in men: what else to rule out

When both appear together, a few other causes are worth naming at your visit:

• Nerve problems. Parkinson's disease, diabetes and spinal cord injury appear on the NIDDK lists for both constipation and urinary retention.^5,2
• A back problem pressing on nerves. New bowel or bladder control problems together with back pain or numbness between the legs can be an emergency. See enlarged prostate and back pain for the red flags.
• Other causes of frequent urination, covered in frequent urination in men over 50.

When to see a doctor

The NIDDK advises seeing a doctor right away if you have constipation with any of these: bleeding from the rectum, blood in the stool, constant belly pain, inability to pass gas, vomiting, fever, lower back pain, or weight loss without trying.^4,5 On the urinary side, get care right away if you cannot urinate at all or have severe pain in your lower belly; the NIDDK says acute urinary retention "can be life threatening."²

At the visit, the NIDDK says a health care professional may ask what medicines you take, prescription and over-the-counter, how much you drink each day, and whether you have caffeine or alcohol, and may do a digital rectal exam, a urinalysis and a PSA blood test.¹ Mention the bowel symptoms even if the appointment is about urination; they change what the exam and the medicine list mean.

For everything else, a regular visit works. Bring a one-week log of bowel movements and bathroom trips, your full medicine list, and a symptom score from our IPSS score calculator. If the score drops after the constipation is treated, that tells you and your doctor something useful.

Where a supplement fits

No prostate supplement treats constipation, and adding pills is not the first step when the bowel is part of the problem. Iron and some other supplements can make constipation worse, so check what you already take before adding anything.⁵ If, after a checkup, you are considering a supplement for urinary symptoms, read its label first: each ingredient, its amount, and whether it matches the studies. Our guide on how to read a prostate supplement label shows how.

A practical plan for this week

1. Today: take the IPSS and write the total down.
2. For 7 days: log bowel movements, bathroom trips and when you drink.
3. Shift fluids earlier in the day instead of cutting them, and add fiber a little at a time.
4. Check your medicine list against the table above and bring questions to your pharmacist.
5. After 4 weeks: retake the IPSS. If the bowel improved and the score dropped, you have found part of the answer.

Frequently asked questions

About the author

Alice Hess is a health researcher and wellness writer at ProstateClarity. She is not a doctor, a nurse, a nutritionist or any kind of licensed clinician, and nothing here is medical advice. She started this work because of her father: at 76 he was getting up several times a night, and the research she did for him helped him get back to sleeping through the night. One man's story is not evidence, which is why every guide here is built on published research. She reads labels, primary research and regulatory limits, and publishes the numbers manufacturers leave out. More about her work and how these articles are researched.

Found an error? Write to contact@prostateclarity.com with the sentence and the source that contradicts it. Corrections are made in the article with the date noted.