Oliguria is the medical term for a decreased output of urine. Oliguria is considered to be a urinary output of less than 400 milliliters, which is less than about 13.5 ounces over the course of 24 hours.

The absence of urine is known as anuria. Less than 50 milliliters or less than about 1.7 ounces of urine in a 24-hour period is considered to be anuria.

There are many potential causes of oliguria. These range from temporary conditions to more serious illnesses.


Dehydration is the most common cause of decreased urine output.

Typically, dehydration occurs when you’re ill with diarrhea, vomiting, or another illness, and can’t replace the fluids that you’re losing. When this happens, your kidneys retain as much fluid as possible.

Infection or trauma

Infection or trauma are less typical causes of oliguria. These can cause the body to go into shock. This reduces the blood flow to your organs.

Shock is a medical emergency and requires immediate attention.

Urinary tract obstruction

A urinary tract obstruction or blockage, occurs when urine can’t leave your kidneys. This can affect one or both kidneys and usually results in a decreased urine output.

Depending on how fast the obstruction occurs, a blockage can also cause other symptoms, such as:


Some medications may cause you to produce less urine.

Medicines that are known to possibly cause this include:

If your medication causes you to release less urine, you should discuss your concerns with your doctor. They may change your medication or adjust your current dosage.

Never change or stop taking a medication without first consulting your doctor.

You should always alert your doctor if you experience decreased urine output. If you don’t already have a primary care provider, you can browse doctors in your area through the Healthline FindCare tool.

You should seek emergency medical attention if you feel that your body may be going into shock. This could be due to a serious infection or trauma that needs quick medical treatment.

You should also seek immediate medical help if you think an enlarged prostate or other condition may be blocking your urinary tract. A blocked urinary tract can quickly develop into anuria. Anuria requires immediate treatment to prevent serious damage to the kidneys.

Call your doctor right away if you have a decreased urine output along with:

  • dizziness
  • rapid pulse
  • lightheadedness

There are no self-treatment options for a decreased urine output. Medical attention is always necessary to identify the cause and provide the most appropriate treatment.

During your appointment, your doctor will ask you a number of questions before making a diagnosis. They’ll probably want to know when the decreased output began, whether it occurred suddenly, and if it has gotten any worse since it started.

It may help if you know approximately how much liquid you drink each day. You should also know whether drinking more increases your urine output and how much urine you’re producing daily.

Your doctor may need you to give a urine sample or at least try. They’ll analyze it for color, protein, and uric acid levels. They’ll also test the sample for any signs of infection.

Make sure to tell your doctor about any other symptoms that you have, any medications or herbal supplements that you take, and whether you have a history of problems with your kidneys or bladder.

You may require additional tests. These could include:

Your treatment will depend on the cause of your oliguria. Your doctor may prescribe an IV drip that quickly rehydrates your body or dialysis to help remove toxins until your kidneys can work correctly again.

You may also want to use special drink mixes to replace any electrolytes lost during this time and prevent oliguria.

The outlook for someone with oliguria depends on the cause of the condition. If it’s left untreated, it’s possible that decreased urine output can cause medical complications, such as:

Most cases require medical treatment. Speak with your doctor as soon as you experience oliguria to develop a treatment plan that works best for you.

In general, you can’t prevent decreased urine output when it’s due to a medical condition. However, the most common cause of this symptom is dehydration. You can avoid dehydration by ensuring that you remain hydrated at all times.

Be sure to increase your fluid intake whenever you have a fever, diarrhea, or other sickness. You may also want to use special drink mixes to replace any electrolytes lost during this time and prevent oliguria.