Version July 2025
Please read the Disclaimer at the end of this page.
What is flank pain? —
This is pain in the side and back between the ribs and hips. It can happen for different reasons. It can develop over time or start suddenly, and can be mild or severe. A person might feel the pain on 1 or both sides.
Flank pain can feel sharp or crampy, or dull and steady. Some people feel better if they curl into a ball, while others need to lie flat and completely still. People might feel nauseous from the pain or vomit.
Sometimes, flank pain can be so severe that the person has a hard time moving or breathing. Severe pain can be a medical emergency, and the person should be seen by a doctor or nurse right away.
What causes flank pain? —
Lots of different things can cause it. They include:
●Injuries, sprains, or problems with the muscles and ribs
●Kidney stones – These can form when salts and minerals that are normally in the urine build up and harden. They can cause pain when they pass through the ureters, which are the tubes that carry urine from the kidney to the bladder.
●Kidney infection – This is when bacteria travels to the kidneys.
●Shingles – This is a painful rash that is usually shaped like a band. The pain often starts several days before the rash develops.
●Pneumonia – This is an infection of the lungs. Sometimes, it can cause flank pain that gets worse when you breathe in or cough.
●Testicular or ovarian torsion or inflammation
●Problems with blood vessels in the belly (like a bulging or ballooning of the aorta)
●Certain types of cancers (like kidney cancer)
●Blood clots in the lungs
Will I need tests? —
Probably. The doctor or nurse will ask about your symptoms, including where your pain is and what it feels like. The location of the pain can be an important clue to the cause.
Your doctor will ask about your current and past medical conditions, and do a physical exam. They might do repeat exams over time to follow your symptoms.
They will decide which tests you should have based on your symptoms and individual situation. The tests might include:
●Blood tests
●Urine tests
●X-rays
●An ultrasound, CT scan, or other imaging test – These create pictures of the inside of the body.
How is flank pain treated? —
Treatment depends on what's causing the pain. It might include 1 or more of the following:
●Fluids given by IV (a thin tube that goes into a vein)
●Pain medicines
●Antibiotic medicines to treat an infection
●Other medicines to treat other medical conditions
●Surgery
How do I care for myself at home? —
Ask the doctor or nurse what you should do when you go home. Make sure that you understand exactly what you need to do to care for yourself, which will depend on the cause of the pain. Ask questions if there is anything you do not understand.
●Pay attention to when you have pain to help your doctor learn more about the cause. Write down the foods you eat to see if they might be causing your pain. Also write down what you were doing before and during the pain.
●The doctor might recommend that you take an over-the-counter pain medicine. These include acetaminophen (sample brand name: Tylenol), ibuprofen (sample brand names: Advil, Motrin), and naproxen (sample brand name: Aleve).
●Some people get a prescription for stronger pain medicines to take for a short time. Follow the instructions for taking these.
●Avoid foods or drinks that make your pain worse. Based on the cause of your pain, it might help to avoid or limit:
•Drinks that are fizzy or have caffeine
•Fried, greasy, or fatty foods
•Milk or cheese
●Ice and heat might help ease the pain:
•Put a cold gel pack, bag of ice, or bag of frozen vegetables on the painful area every 1 to 2 hours, for 15 minutes each time. Put a thin towel between the ice (or other cold object) and the skin.
•Put a heating pad on the painful area for no more than 20 minutes at a time. Also, do not use anything too hot that could burn your skin. Never go to sleep with a heating pad on since this can cause burns.
When should I call the doctor? —
Call for emergency help right away (in the US and Canada, call 9-1-1) if:
●Your flank pain becomes severe, and does not get better with the care described above.
●You have trouble breathing, or start having chest pain along with your flank pain.
●You vomit blood or pass a lot of blood in your stool, or your bowel movements are black or tar colored.
●Your belly becomes very hard or swollen.
You might need emergency help if:
●You have a fever of 100.4°F (38°C) or higher, or chills.
●Your bladder feels full, and you cannot pass urine for more than 6 hours.
●You have nausea or vomiting that isn't getting better, and are having trouble keeping down food and drink.
●You have signs of fluid loss, such as:
•No urine for more than 8 hours, or very dark-colored urine
•Feeling very lightheaded, or like you are going to pass out
•Feeling weak, like you are going to fall
Call for advice if:
●Your pain gets worse, comes more often, or moves to 1 area of the belly.
●Your bowel movements have a small amount (less than 1 teaspoon, or 5 mL) of blood in them.
●You have pain when urinating, or have blood in your urine.
●Your pain is not gone or getting better in 1 to 2 days.
Patient education: Muscle strain (The Basics)
Patient education: Rib injury in adults (The Basics)
Patient education: Abdominal pain (The Basics)
Patient education: Kidney stones in adults (The Basics)
Patient education: Kidney stones in children (The Basics)
Patient education: Urinary tract infections in adults (The Basics)
Patient education: Urinary tract infections in children (The Basics)
Patient education: Shingles (The Basics)
Patient education: Pleuritic chest pain (The Basics)
Patient education: Chronic abdominal pain in children and adolescents (Beyond the Basics)
Patient education: Kidney stones in adults (Beyond the Basics)
Patient education: Kidney stones in children (Beyond the Basics)
Patient education: Urinary tract infections in adults (Beyond the Basics)
Patient education: Urinary tract infections in children (Beyond the Basics)
Patient education: Shingles (Beyond the Basics)
