The most important things you can do for someone passing a kidney stone are managing their pain, keeping them hydrated, and knowing when the situation requires emergency care. Most stones under 4 mm pass on their own within one to two weeks, but those weeks can be miserable. Here’s how to make the process as bearable as possible.
Know What Size You’re Dealing With
Stone size is the single biggest factor in whether someone can pass a stone at home or needs medical intervention. If the person hasn’t had imaging yet, that’s the first step. A non-contrast CT scan is the gold standard for measuring stone size, density, and location. Ultrasound is a reasonable starting point and is the preferred option for pregnant patients.
The passage rates by stone width tell a clear story:
- Under 3 mm: 98% pass on their own
- 4 mm: about 81% pass
- 5 mm: about 65% pass
- 6 mm: only 33% pass
- Over 6.5 mm: just 9% pass without a procedure
Stones under 4 mm typically pass within one to two weeks. Larger stones can take two to three weeks. Once a stone reaches the bladder, it usually comes out within a few days. Knowing the size helps set expectations and determines whether home care is appropriate or a urologist needs to get involved sooner.
Help Them Stay on Top of Pain
Kidney stone pain (renal colic) can be excruciating, often described as worse than childbirth. It comes in waves as the stone moves through the ureter, and the person you’re helping may not be able to think clearly enough to manage their own care during a flare.
Anti-inflammatory painkillers like ibuprofen or naproxen are the best first-line option. A large meta-analysis of 11 randomized trials found that NSAIDs provided the most sustained pain relief for kidney stone episodes, with fewer side effects than opioids. People taking NSAIDs experienced significantly less vomiting and were less likely to need additional rescue medication compared to those taking opioids or acetaminophen. Acetaminophen works about equally well in the first 30 minutes, but people taking it are more likely to need a second dose or additional pain relief later. Help the person stay on a consistent schedule rather than waiting for the pain to become unbearable before taking another dose.
Heat also makes a real difference. A randomized controlled trial found that applying a heat patch to the affected flank area significantly reduced pain scores within 30 minutes, and only 11.5% of patients using heat needed additional pain medication compared to 31.4% without it. A heating pad, hot water bottle, or warm bath can serve the same purpose. Keep one ready so you can offer it the moment a pain episode starts.
Push Fluids Aggressively
Drinking enough water is the single most effective thing someone can do to help a stone pass. The goal is to produce 2 to 2.5 liters of urine per day. For most people, that means drinking roughly 2.5 to 3 liters of water daily, since some fluid is lost through sweat and breathing. One study found that adding about 1.3 liters of water above a person’s normal intake was enough to hit these targets.
This is where your help matters most. Someone in severe pain, possibly nauseated, often won’t drink enough on their own. Keep a filled water bottle within arm’s reach at all times. Track how much they’re drinking. Set gentle reminders. If they’re vomiting and can’t keep fluids down, that’s a reason to seek emergency care, because dehydration will stall the stone and worsen pain.
Adding lemon juice to water can help. Citrate, the active compound in lemon juice, binds to calcium and may slow stone growth during the passing process. Research has used about 85 milliliters of fresh lemon juice per day (roughly one-third of a cup) as a therapeutic dose. Squeezing fresh lemons into their water throughout the day is an easy way to incorporate this.
Set Up a Stone Strainer
Catching the stone matters more than most people realize. Once someone has had one kidney stone, they’re significantly more likely to form another. A lab analysis of the stone reveals exactly what it’s made of, which allows a doctor to recommend specific dietary changes or medications to prevent recurrence.
You can buy a kidney stone strainer at most pharmacies. It’s a small mesh screen that fits over a toilet or collection cup. The person needs to filter every single time they urinate, day and night, until the stone is caught. The stone can be tiny, resembling a grain of sand or a small piece of gravel, so checking the strainer carefully each time is important. Once found, place it in a clean, dry container with a lid. Don’t wrap it in tissue or add any liquid. Return it to the doctor’s office for analysis.
Your role here is practical: make sure the strainer is always in position, remind them to check it (especially during groggy nighttime bathroom trips), and have a clean container ready.
Know When to Go to the ER
Most kidney stones pass without complications, but certain symptoms signal a potential emergency. Get the person to an emergency room if they experience:
- Fever and chills: this suggests an infection behind the stone, which can become life-threatening quickly
- Pain so severe they can’t sit still or find any comfortable position
- Persistent vomiting that prevents them from keeping down fluids or medication
- Blood in the urine (some pink tinges are normal, but heavy or persistent bleeding warrants evaluation)
- Inability to urinate: this may indicate the stone is completely blocking the ureter
A blocked, infected kidney is a urological emergency. If fever accompanies stone symptoms, don’t wait to see if it improves.
What to Expect Day to Day
The pain pattern of a kidney stone is not constant. It tends to come in intense waves lasting 20 minutes to an hour as the stone shifts and the ureter spasms around it, followed by periods of relative calm. The worst pain typically occurs when the stone is in the lower ureter, near the bladder. Once it drops into the bladder, the intense flank pain usually stops, and the remaining discomfort during urination is comparatively mild.
Help the person keep a loose schedule during this time. They may feel fine for hours and then suddenly be unable to do anything but lie on the floor. Having pain medication, a heating pad, and water within reach at all times reduces the scramble when an episode hits. Driving them to appointments, handling meals, and simply being present during the worst pain flares makes a bigger difference than it might seem. Kidney stones are isolating, and the unpredictability of the pain can be psychologically draining even between episodes.
If the stone hasn’t passed after three weeks, or if imaging shows it’s too large to pass on its own, the doctor will discuss procedural options. These range from sound wave therapy that breaks the stone into smaller fragments to minimally invasive procedures using a small scope threaded through the urinary tract. Recovery from these procedures is typically quick, often just a few days.