Medical Articles · 5 min read
Can Kidney Stones Pass Naturally?
In brief
Yes — many small kidney stones pass on their own, particularly those under about 5 mm, usually within a few weeks. Larger stones are less likely to pass. Fluids, pain relief and sometimes an alpha-blocker can help, but stones causing infection, uncontrolled pain or blockage need prompt treatment.
Medically reviewed by Dr. Atip Chatsudthipong, MD on
Written by Editorial teamPublished Updated
Does the size of the stone matter?
Yes. Stone size and position are the main factors. Small stones, particularly under about 5 mm and those already in the lower ureter near the bladder, are the most likely to pass. Stones larger than about 10 mm rarely pass without help.
How long does it take to pass a kidney stone?
Many stones pass within a few weeks. If a stone has not passed within about four to six weeks, guidelines generally recommend treatment, because prolonged blockage can harm the kidney.
What helps a kidney stone pass?
- Pain relief, as advised by your doctor
- Drinking enough fluid — without forcing excessive amounts
- For some stones in the lower ureter, an alpha-blocker medicine (medical expulsive therapy)
- Straining the urine so the stone can be sent for analysis
When is treatment needed?
Seek emergency care immediately if you have:
- Stone pain with fever or chills
- Pain not controlled with medication, or persistent vomiting
- Very little or no urine
A procedure such as ureteroscopy with laser or shock wave lithotripsy is usually advised if a stone is unlikely to pass, has not passed after a period of observation, or is causing complications. See Kidney stone treatment options explained.
Frequently asked questions
Does drinking lots of water flush out a kidney stone?
Staying well hydrated helps, but drinking excessive amounts does not push a stone through faster and can worsen discomfort if the kidney is blocked. Follow your doctor's advice.
References
- 1.Assimos D, et al. Surgical Management of Stones: American Urological Association/Endourological Society Guideline, Part I. J Urol. 2016;196(4):1153–1160. (opens in a new tab)
- 2.European Association of Urology. EAU Guidelines on Urolithiasis. (opens in a new tab)
- 3.National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Kidney Stones. (opens in a new tab)
This information is for general education and does not replace a consultation with a qualified doctor. If you have severe symptoms, seek emergency care (in Thailand, call 1669). See our medical disclaimer.