How to Pass a Kidney Stone: How Long It Takes and What Helps
Many small kidney stones pass on their own. A monitored trial of passage usually means pain control, normal hydration (not forced gallons of water), sometimes a medicine such as tamsulosin to relax the ureter, straining your urine, and follow-up imaging. For an uncomplicated stone under about 6 mm, a trial of about four weeks is a common frame, stretching toward six weeks only if imaging shows the stone moving and the kidney draining. Fever, uncontrolled pain or vomiting ends the wait right away.
This guide explains what helps a stone pass, how long it can take, which medicines are used, and when it is time to stop waiting.
Will my stone pass on its own?
Size matters, but it is not the whole answer. Very small stones in the ureter, the thin tube from the kidney to the bladder, frequently pass without a procedure, especially when they are already in the lower (distal) ureter near the bladder. As size increases, passage becomes less predictable. Smaller stones low in the ureter generally have a better chance than larger stones higher up.
Other factors also count: the stone's exact location, your anatomy, whether the pain is controlled, whether there is infection, your kidney function, how long the stone has already been blocking, your past stone history, pregnancy, blood thinners, your job and travel plans, and your own preferences. Published passage percentages vary, and no statistic can promise what your particular stone will do. Ask which measurements were taken on your scan and how they affect your plan.
What actually helps a stone pass
Watchful waiting is not "do nothing." It is an active plan agreed with your doctor. It usually includes:
- Pain control. Anti-inflammatory medicines (NSAIDs) are often very effective for stone pain when they are safe for your kidneys, stomach, heart and other medicines. Acetaminophen may be part of the plan, and an opioid may be used as rescue for severe pain. Follow the prescribed dose and duration.
- Normal hydration. Avoid dehydration, but do not chug large volumes of water to "flush" the stone. Forcing fluids into a blocked ureter has not been shown to speed passage and can make the pain worse. Small, regular sips may be easier if you feel sick.
- Medicine to relax the ureter, in selected cases (see below).
- Straining your urine every time you go, so you can catch the stone.
- Follow-up with imaging and a clear date to decide what comes next.
Two things do not help. Water will not dissolve a calcium stone that has already formed. And over-the-counter "stone breaker" supplements are unregulated; some contain plant extracts that can raise urine oxalate or affect the liver. Only pure uric acid stones can sometimes be dissolved, over months, with prescription medicine that makes the urine less acidic.
Medications: tamsulosin and pain relief
Tamsulosin is an alpha-blocker first developed for prostate enlargement. The ureter's muscle has the same receptors, so relaxing it may help some stones pass. Doctors call this medical expulsive therapy. Tamsulosin is used off label for this purpose.
The clearest benefit is for stones in the lower ureter larger than about 5 mm and up to about 10 mm. Smaller stones often pass without it. It does not dissolve a stone, it does not open a fully blocked system, and it does not replace drainage when drainage is urgently needed.
Possible side effects include dizziness, low blood pressure when standing, nasal congestion, tiredness and changes in ejaculation. Your doctor will weigh your blood pressure, other medicines and fall risk.
For pain, NSAIDs such as ketorolac can work well, but they carry kidney, stomach, bleeding and heart risks, especially if you are dehydrated or have kidney disease. Do not combine NSAIDs or keep taking them indefinitely. If you need repeated rescue doses despite a good plan, that is a sign home care may be failing, not a reason to keep escalating.
How long does it take to pass a kidney stone?
Many stones that are going to pass do so within several weeks. For an uncomplicated stone under about 6 mm, about four weeks is a typical trial, roughly the 30-day frame used for medical expulsive therapy. It can stretch toward six weeks only when imaging shows the stone moving and the kidney draining.
The calendar is only one checkpoint. If the stone has not moved by the agreed review, or if swelling of the kidney is getting worse, the plan should change to a procedure. A stone that is moving with improving symptoms may deserve more time; a stone that stays stuck and keeps sending you to the emergency room may not. Watchful waiting is a timed trial, not an open-ended wait.
Signs the stone has passed, and what to do next
Some people feel a brief pop or pressure at the base of the bladder and hear a small click in the strainer. Others notice nothing. Relief from pain is a good sign, but it does not prove the stone is gone or that the kidney is draining. If you did not catch the stone, follow-up imaging may be needed, especially if there was significant blockage.
If you catch the stone, let it dry and put it in a clean container. Do not store it in toilet water or a household chemical. Even tiny pieces can be analyzed. The analysis tells you what the stone is made of and steers prevention. See types of kidney stones and how to prevent kidney stones.
When to stop waiting
Agree on the stopping rules at the start. Seek urgent care for:
- Fever of 100.4°F or more, or shaking chills. An infected, blocked kidney is an emergency that usually needs drainage, not more waiting.
- Pain your medicine cannot control.
- Vomiting that keeps you from holding down fluids or medicine.
- Much less urine than usual, or none.
- Feeling faint, confused or generally very unwell.
- Any of these if you are pregnant, have one kidney, a transplant kidney or significant kidney disease.
Serious infection can happen without a high fever, particularly in older or immunocompromised people. Read more in kidney stone pain: when to go to the ER.
Moving on to a procedure is not failure. If the stone does not pass, shockwave lithotripsy is the least invasive option when the stone fits, and ureteroscopy is another. See kidney stone treatment options. A urologist can set up a safe trial of passage and tell you when it is time to act.
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Frequently asked questions
- How long does it take to pass a kidney stone?
- Many stones that will pass do so within several weeks. For an uncomplicated stone under about 6 mm, about four weeks is a common trial, longer only if imaging shows the stone moving and the kidney draining.
- Does drinking lots of water help pass a stone?
- Stay normally hydrated, but do not force large volumes. Forcing fluids into a blocked ureter has not been shown to speed passage and can worsen pain.
- What does tamsulosin do for kidney stones?
- It relaxes the muscle of the ureter and may help some stones pass, with the clearest benefit for stones in the lower ureter between about 5 and 10 mm. It does not dissolve the stone.
- Should I keep the stone after it passes?
- Yes. Let it dry, put it in a clean container and bring it to your doctor. Stone analysis shows what it is made of and guides prevention.
- When should I stop waiting for a stone to pass?
- Right away if you have fever or chills, pain you cannot control, vomiting that stops you keeping fluids down, or much less urine. Otherwise at the checkpoint agreed with your doctor if the stone has not moved.