Lactic acidosis occurs when a person’s body either produces too much lactate, or underuses lactate. Lactic acidosis can be caused by conditions such as heart disease, HIV, cancer, and more.

Lactic acidosis is a form of metabolic acidosis, a condition in which there’s too much acid in the body. Lactic acidosis begins when a person’s body makes too much lactate or underuses lactate and isn’t able to adjust to these changes.

In people with lactic acidosis, problems with the liver (and sometimes with the kidneys) make these organs unable to remove extra acid from their bodies. If lactate builds up in the body faster than it can be removed, acid levels spike in bodily fluids like blood.

This buildup of acid causes an imbalance in the body’s pH level, which should always be slightly basic, or alkaline, instead of acidic. There are a few different types of acidosis.

Lactate buildup occurs when there’s not enough oxygen in the muscles to break down, or metabolize, the blood sugars glucose and glycogen. Metabolism without oxygen is called anaerobic metabolism.

There are two forms of lactate: L-lactate and D-lactate. Most forms of lactic acidosis are caused by too much L-lactate.

There are two types of lactic acidosis, Type A and Type B:

  • Type A lactic acidosis is caused by a lowered amount of blood flow in the tissue, called hypoperfusion. Hypoperfusion can be caused by hypovolemia (a lowered blood volume), heart failure, sepsis (the spread of infection to the bloodstream), or cardiac arrest (when the heart stops beating).
  • Type B lactic acidosis is caused by impaired cell function and lowered blood flow that’s limited to certain areas of tissue.

Lactic acidosis has many causes and can often be treated. But if left untreated, it may be life threatening.

The symptoms of lactic acidosis are typical of many health conditions. If you experience any of these symptoms, you should contact a doctor immediately. A doctor can help find the root cause.

Several symptoms associated with lactic acidosis represent a medical emergency:

  • fruity-smelling breath (a possible symptom of a serious complication of diabetes called ketoacidosis, which is caused by a buildup of chemicals known as ketones)
  • confusion
  • jaundice (yellowing of the skin or the whites of the eyes, caused by liver impairment, which can lead to lactic acidosis)
  • trouble breathing or shallow, rapid breathing

If you know or suspect that you have lactic acidosis and have any of these symptoms, call 911 or go to an emergency room right away.

Other lactic acidosis symptoms include:

  • exhaustion or extreme fatigue
  • muscle cramps or pain
  • body weakness
  • overall feelings of physical discomfort
  • abdominal pain or discomfort
  • diarrhea
  • decrease in appetite
  • headache
  • rapid heart rate

Lactic acidosis has a wide range of underlying causes, including carbon monoxide poisoning, cholera, malaria, and suffocation. Some common causes include:

Heart disease

Conditions like cardiac arrest and congestive heart failure may reduce the flow of blood and oxygen throughout the body. This can increase lactate levels.

Severe infection (sepsis)

Any type of severe viral or bacterial infection can cause sepsis. People with sepsis may experience a spike in lactate caused by lowered oxygen flow.


HIV medications, like nucleoside reverse transcriptase inhibitors, can cause lactate levels to spike. They also may cause liver damage. This makes it harder for the body to process lactate.


Cancer cells create lactate. This buildup of lactate may accelerate as a person loses weight and the disease progresses.

Short bowel syndrome (short gut)

People with short gut may experience a buildup of D-lactate caused by bacterial overgrowth in the small bowel, although this is rare. People who’ve had gastric bypass surgery may also develop D-lactic acidosis.

Acetaminophen use

Regular, frequent use of acetaminophen (Tylenol) can cause lactic acidosis, even when it’s taken at the correct dosage. This is because it can cause an accumulation of pyroglutamic acid, an amino acid byproduct, in the blood.

Alcohol use disorder

Consuming too much alcohol over an extended period of time can lead to lactic acidosis and “alcoholic ketoacidosis.” If left untreated, this type of ketoacidosis is a potentially fatal condition, but it can be combated with intravenous (IV) hydration and glucose.

Consuming too much alcohol can also lead to acute liver disease (hepatitis) or chronic liver disease (cirrhosis), which are both associated with lactic acidosis.

Alcohol increases phosphate levels, which negatively impacts the kidneys. This makes the body’s pH more acidic. If you’re having trouble lowering your alcohol intake, support groups can help.

Generalized tonic-clonic seizures

Generalized tonic-clonic seizures, formerly known as grand mal seizures, consist of tonic (stiffening) and clonic (twitching or jerking) phases of muscle activity caused by abnormal electrical activity throughout the brain.

A 2016 study showed that people with observed tonic-clonic seizures and known epilepsy had signs of elevated lactate levels 2 hours after a seizure.

Use of some medications

Medications like epinephrine (used to treat allergic reactions) and albuterol (used to treat shortness of breath) were shown in a 2019 study to cause lactic acidosis.

In this study, 86 percent of ingested doses that caused lactic acidosis were Food and Drug Administration (FDA)-labeled doses.

A specific class of oral diabetes medication called biguanides can cause a buildup of lactate levels.

Though not significantly associated with lactic acidosis risk, metformin (Glucophage) is one of these drugs. It’s used to treat diabetes and may also be prescribed for other conditions. Metformin is also used off label to treat polycystic ovarian syndrome, a hormonal condition that causes ovaries to get larger and develop small growths.

In people with diabetes, lactic acidosis may be more of a concern if kidney disease is also present. If you have diabetes and experience any symptoms of lactic acidosis, call 911 or go to an emergency room immediately.

Lactic acidosis is diagnosed through a fasting blood test. A doctor may instruct you not to eat or drink anything for 8 to 10 hours before taking the test. You may also be instructed to lower your activity level in the hours leading up to the test.

During the test, your doctor may tell you not to clench your fist, as this may cause acid levels to spike. Tying an elastic band around the arm may also have this result.

For these reasons, blood may sometimes be taken from a vein on the back of the hand instead of from one in the arm for a lactic acidosis blood test.

The best way to treat lactic acidosis is by treating its root cause. For that reason, treatments vary.

Lactic acidosis is sometimes a sign of a medical emergency. Such cases require treating symptoms, regardless of their root cause. Increasing oxygen to the tissues and giving IV fluids are often used to lower lactic acid levels.

Depending on the root cause, treatments for lactic acidosis often result in full recovery, particularly if treatment is provided quickly. Sometimes, kidney failure or respiratory failure may result. When left untreated, lactic acidosis can be fatal.

How you prevent lactic acidosis also depends on the possible cause. If you have diabetes, HIV, or cancer, discuss your condition and the medications you need with a doctor.

It’s very important to avoid misusing alcohol. Discuss treatment and 12-step program options with a doctor or counselor.