Health TopicsInflammation


Inflammation protects the body against germs and promotes healing, but too much can be harmful. Learn about inflammation, inflammatory foods, and more.


Inflammation is a bodily response that helps injuries heal and protects you against threats like germs. For instance, if you cut your finger, inflammation causes the temporary swelling and discoloration that’s part of the healing process. Brief periods of inflammation in response to injuries, infections, or exposure to toxins are essential to keeping you healthy. But inflammation that lasts for long periods of time (chronic inflammation) can lead to a range of health issues.

Discover the basics of inflammation, including its types, the reasons inflammation happens, and when it can do more harm than good. Learn about foods that cause inflammation and the facts behind anti-inflammatory diets, plus how you can take steps to reduce inflammation in your body.

What is inflammation?

Senior woman rubbing her painful inflamed hands

Inflammation is a tool of your body’s immune system, the network of tissues, cells, and organs that defends against health threats like germs. When your immune system detects a potential source of harm, it sends white blood cells to surround an injury or to attack and neutralize invaders such as bacteria, viruses, toxins, or allergens. This response, combined with an increase in temperature and the widening of blood vessels around the affected area, is called inflammation or an inflammatory response.

Inflammation is one way your body begins to heal damaged tissues and prevent infections from worsening. Without inflammation, wounds would persist and minor infections could turn deadly.  

An inflammatory response may temporarily result in swelling, discoloration, bruising, pain, or warmth. Fever may also occur in response to an illness or infection. These are signs that your immune system is working. Inflammation also affects parts of your body in ways that you can’t see or feel.

Although temporary (acute) inflammation is often necessary and beneficial, inflammation that doesn’t resolve on its own and becomes chronic can become harmful. Chronic inflammation may contribute to the development of conditions including cancer, Parkinson’s disease, type 2 diabetes, Alzheimer’s disease, and rheumatoid arthritis. These are often referred to as inflammatory conditions.

How are cytokines related to inflammation?

Understanding the role of cytokines can help explain inflammation and how it can become problematic.

Cytokines are small proteins that regulate inflammation and work as messengers in your immune system. There are two general types of cytokines, those that promote inflammation (pro-inflammatory cytokines) and those that reduce it (anti-inflammatory cytokines).

When your immune system perceives a threat, pro-inflammatory cytokines prompt immune cells to trigger inflammation. These cytokines also instruct immune cells on how to target harmful substances or to heal damaged tissues.

Once the threat is addressed by the immune system, anti-inflammatory cytokines send messages to reduce or stop inflammation. This prevents excessive inflammation that can damage tissues instead of healing them.  

Having too many pro-inflammatory cytokines or problems with anti-inflammatory cytokines can lead to chronic inflammation. Several factors can affect cytokines and the immune system, from the foods you eat to medical conditions you may have to your exposure to toxins.

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What are the types of inflammation?

There are two main types of inflammation:

Acute inflammation

The inflammation that occurs immediately in response to injury or illness is called acute inflammation. It works to neutralize harmful substances like viruses and promote healing. You may recognize acute inflammation as the swelling, pain, warmth, or bruising you experience after twisting an ankle or cutting your finger.

Acute inflammation is temporary and usually resolves on its own in a few hours or days. Inflammation that persists for two to six weeks is called subacute inflammation, which is viewed as a transitional form between acute and chronic inflammation.

Chronic inflammation

Chronic inflammation refers to persistent, low-grade inflammation that lingers for six weeks or longer. These low levels of inflammation can occur when acute inflammation doesn’t completely resolve. Chronic inflammation can last for several months or even years.

With chronic inflammation, your immune system might send a wave of immune cells to respond to an injury or infection that isn’t actually there. Because these immune cells have no real threat to contend with, they may eventually start affecting healthy cells and tissues. This process can lead to a wide range of physical health complications as well as mental health issues like depression.

If left unaddressed, chronic inflammation can become deadly. The National Institute of Environmental Health Sciences says that chronic inflammation plays a role in more than half of all deaths globally. Research shows that three out of five people worldwide die of diseases related to chronic inflammation, such as cancer, chronic obstructive pulmonary disease (COPD), stroke, diabetes, and heart disease.  

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What are the signs and symptoms of inflammation?

Symptoms of acute inflammation tend to come on suddenly and are quickly noticeable. The hallmark signs of acute inflammation include:

  • Flushed skin that may appear red or discolored
  • Swelling
  • Warmth or heat
  • Bruising
  • Pain  
  • Loss of function

Chronic inflammation symptoms can vary widely and usually develop more gradually than acute inflammation symptoms. They may be short-lived or linger for an extended period of time. They may also come and go with time.

Possible signs of chronic inflammation include:

In some cases, chronic inflammation doesn’t cause any noticeable symptoms.  

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What conditions are linked to inflammation?

Inflammation that becomes chronic is linked to a range of health concerns, including:

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What causes inflammation?

Inflammation is triggered by your immune system in response to a perceived threat. These threats can generally be categorized as infectious and non-infectious.

Infectious causes of inflammation are common illnesses like influenza (the flu), COVID-19, colds, strep throat, pneumonia, and urinary tract infections. These illnesses are caused by infectious organisms, including:

  • Bacteria
  • Viruses 
  • Fungi
  • Parasites

Non-infectious causes of inflammation include, but aren’t limited to:

  • Physical trauma, such as a cut, broken bone, or sprained joint
  • Burns
  • Frostbite  
  • Allergens such as dust mites, pollen, and mold
  • Harmful foreign substances, such as silica and asbestos  
  • Exposure to toxins such as pollution, cigarette smoke, and industrial or environmental chemicals
  • Chemical signals released by damaged or dying tissues
  • Chronic stress  
  • Certain foods

What foods cause inflammation?

The link between diet and inflammation is strong. Regularly eating certain foods has been shown to cause or worsen chronic inflammation. These include:

  • Added sugars, such as those found in soft drinks, sugary cereals, cakes, candies, fruit drinks, and many processed foods
  • Refined carbohydrates, such as those in white bread, pastries, white rice, and processed potato products
  • Foods that are high in saturated fats, such as processed meats (like hot dogs and sausages), red meat, and full-fat dairy products
  • Foods that are high in trans fats, such as some fast foods, frozen breakfasts, donuts, cookies, fried foods, and margarine
  • Excess amounts of some omega-6 fatty acids, which can be found in cooking oils including vegetable, sunflower, grapeseed, corn, peanut, soybean, and safflower oils

People with celiac disease or a gluten sensitivity may also experience an inflammatory response after eating products that contain gluten. This protein is found in foods made with wheat, barley, rye, malt, and brewer’s yeast.

When does inflammation become chronic?

Acute inflammation caused by infectious or non-infectious factors is considered to become chronic if it persists for more than six weeks. There are a few possible reasons why inflammation may not subside when it should. For example:

  • Your body is unable to eliminate the agent (such as a virus, allergen, or toxin) that caused the initial inflammatory response.
  • Your immune system perceives and responds to a threat that isn’t actually harmful. This is the case with autoimmune disorders like lupus and rheumatoid arthritis, which cause your immune system to attack healthy tissues.
  • You smoke, frequently eat foods that cause inflammation, live a sedentary lifestyle (one that involves lots of sitting), or engage in other behaviors that can increase your risk of ongoing inflammation (see more below).

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What are the risk factors for chronic inflammation?

For most people, an episode of acute inflammation subsides when the body deals with the issue that caused the inflammation. For example, a fever typically passes after a day or so of having the flu when the body neutralizes the flu virus. The swelling and pain from a sprained ankle eases once the joint begins to heal. Or an inflamed airway settles down when the smoke clears after a forest fire near your home.

But for many people, the body’s ability to resolve inflammation is limited or compromised by other underlying conditions, lifestyle habits, or health issues. For example, you may be more likely to experience chronic inflammation if you:

You might be wondering how much alcohol is too much. The answer to that question can vary, but the Centers for Disease Control and Prevention (CDC) advises people assigned female at birth to limit their alcohol consumption to one drink per day, while people assigned male at birth should consume no more than two drinks per day.

One drink is defined as:

  • 1.5 ounces of a distilled spirit, such as gin, vodka, rum, whiskey, and tequila
  • 5 ounces of wine
  • 8 ounces of malt liquor, such as malt-based hard seltzer
  • 12 ounces of beer   

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How is inflammation measured?

Healthcare providers (HCPs) may use several blood tests to measure inflammation levels in the body. Some tests for inflammation include:

C-reactive protein (CRP) test: This test measures the amount of CRP in blood. CRP is a protein that’s produced by the liver and usually rises in response to inflammation. A typical amount of CRP is around 3 milligrams (mg) per liter (L) of blood, but inflammation that’s present throughout the body may cause CRP levels to jump to 100 mg/L or higher.   

Erythrocyte sedimentation rate (ESR) test: This test observes how quickly red blood cells fall to the bottom of an upright tube of blood. Inflammation makes red blood cells clump together, weighing them down and causing them to fall faster than they normally would.  

Fibrinogen test: High levels of blood fibrinogen can indicate inflammation. Fibrinogen is a protein that’s most commonly used to measure the health of the body’s blood clotting system (the process by which blood clumps together to slow down bleeding).

Ferritin test: Ferritin is a blood protein that’s related to how much iron you have in your body. A ferritin test is usually used to screen for anemia or hemochromatosis (too much iron), but high levels of ferritin can also indicate inflammation.

One drawback of blood tests for inflammation is that they can’t distinguish between acute and chronic inflammation. Because of this, regular inflammation testing isn’t recommended by most HCPs. Tests that measure inflammation are typically only used to help diagnose or monitor certain inflammatory conditions.

Does inflammation show up on imaging tests?

While X-ray imaging usually can’t detect areas of inflammation in the body, other imaging techniques can in some cases. These tests include:

  • Magnetic resonance imaging (MRI)
  • Computed tomography (CT) scans  
  • Positron emission tomography (PET) scans
  • Ultrasound imaging
  • Single-photon emission computed tomography (SPECT) scans 

An HCP may order one of these imaging tests to help diagnose or rule out various inflammatory diseases, among other conditions.  

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When should you see a healthcare provider?

Woman seeing her healthcare providor to discuss issues with inflammation

Developing signs of acute inflammation (such as temporary swelling or bruising) means your immune system is doing its job. While not all causes of inflammation require a trip to an HCP’s office, it’s a good idea to make a visit if you experience an injury, illness, or signs of chronic inflammation that don’t improve with self-care measures like rest, compression, bandaging, and over-the-counter medication.

Some injuries and illnesses require emergency medical attention. Call 911 right away or visit your nearest hospital emergency department (ED) if you or someone near you experiences any of the following:

  • Uncontrollable bleeding
  • Loss of consciousness
  • Difficulty breathing or shortness of breath
  • Chest pain or tightness
  • Sudden changes in vision 
  • Seizure
  • Trouble balancing or walking
  • Numbness or weakness in an arm, leg, or the face
  • Slurred speech
  • Confusion or disorientation
  • An intense, sudden headache  
  • A fever of 103 degrees Fahrenheit or higher in an adult. (A child older than three months should go to the ER if their fever is 102.2 degrees or higher. For a child younger than three months, head to the ER if their rectal temperature exceeds 100.3 degrees.)What questions should you ask your healthcare provider?

Inflammation is a complex process that’s still being explored by researchers. Asking your HCP any questions you may have about acute inflammation, chronic inflammation, and how they relate to your well-being can help you make educated decisions about your health.

Some common questions about inflammation include:

  • Am I at risk for chronic inflammation?
  • What conditions might be caused by inflammation?
  • What causes chronic inflammation in the body?
  • Does being stressed-out cause inflammation? 
  • What warning signs of inflammation should I look out for? 
  • How can I reduce inflammation quickly? 
  • What foods should I eat to lower inflammation? And what foods should I avoid?
  • How can I develop an anti-inflammatory diet for myself?  

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How can you reduce inflammation?

Acute inflammation can often be managed through self-care measures like rest, proper wound care, and ice therapy.

If you’re dealing with chronic inflammation, your HCP may recommend a combination of anti-inflammatory measures, including:

Medications to lower inflammation

  • Nonsteroidal anti-inflammatory drugs (NSAIDs): Over-the-counter NSAIDs like ibuprofen, aspirin, and naproxen can lower inflammation and help ease joint pain. 
  • Corticosteroids: These medicines help lessen symptoms of inflammatory conditions like asthma, lupus, and arthritis by disrupting several processes involved in inflammation. Corticosteroids in injection form can be given to reduce inflammation in a specific area, such as a knee or shoulder. 
  • Statins: This is a class of medications that reduce levels of LDL (aka “bad” cholesterol). They also offer some anti-inflammatory properties. Some HCPs may prescribe statins to help control inflammation and lower the risk of cardiovascular disease.

Exercise to lower inflammation

Frequent, high-intensity workouts can contribute to inflammation by temporarily damaging muscles. But less-rigorous periods of exercise have shown to deliver an anti-inflammatory benefit.

Moderate-intensity exercise and vigorous-intensity exercise with adequate rest breaks can help lower inflammation by stimulating the production of anti-inflammatory hormones. Moreover, increasing physical activity can help you shed excess body fat. Being overweight or obese is a major cause of chronic inflammation and a contributor to numerous health problems.

The CDC recommends that adults get around 150 minutes of moderate-intensity aerobic (known as cardiovascular or “cardio”) exercise per week. That’s around 30 minutes of exercise five days per week. If 30 minutes of physical activity seems daunting, start with a brisk, five- or ten-minute walk most days and gradually work your way up to 30 minutes. Your HCP can also recommend exercises that are appropriate for your age, overall health, and individual needs. 

A few examples of moderate-intensity exercises include:

  • Brisk walking
  • Water aerobics
  • Riding a bike on flat or slightly hilly terrain
  • Playing doubles tennis

If walking isn’t your preferred speed, you can also meet your recommended amount of exercise by shooting for 75 minutes of vigorous-intensity aerobic exercise per week. Examples of these activities include:

  • Running
  • Playing basketball
  • Playing singles tennis
  • Swimming laps 
  • Riding a bike on hilly terrain or at a fast pace

Be sure to speak with your HCP before starting or drastically changing an exercise routine. They can provide information on how to exercise safely and avoid inflammation-causing injuries. Partnering with a physical trainer or exercise physiologist may also be helpful if you’re interested in boosting your health through exercise.

An anti-inflammatory diet

While some foods are known to cause inflammation, many have anti-inflammatory properties. Adopting an anti-inflammatory diet is one way to reduce inflammation in your body, lose excess weight, and improve your overall health.

Research shows that the Mediterranean diet—one of the most popular healthy eating plans—can disrupt harmful inflammatory processes and help lower the risk of cardiovascular disease. This anti-inflammatory diet incorporates some of the heart-healthy eating habits of people who live in regions that border the Mediterranean Sea.

Many anti-inflammatory foods are included in a Mediterranean style of eating, including: 

While not necessarily emphasized in the Mediterranean diet, avocados have powerful anti-inflammatory properties. Green and black teas do, as well. Micronutrients called polyphenols found in tea leaves help lower levels of proteins that are involved in inflammation.

Additionally, several foods that are known to cause or contribute to chronic inflammation are restricted on the Mediterranean-style diet, including:

It’s okay if you can’t fully commit to a Mediterranean-style eating plan. Some of the staples of the eating style—such as fish, olive oil, and nuts—can be expensive. But there are ways to enjoy the Mediterranean style of eating on a budget.

Meanwhile, simply adding more anti-inflammatory foods into your diet and limiting inflammation-promoting items can help lower your risk of inflammatory diseases.

Speak with your HCP to learn more about anti-inflammatory foods and what eating plans may be best for you. It may also be helpful to consult with a nutritionist or dietitian for additional guidance.


Taking certain nutritional and herbal supplements (under the guidance of an HCP) may also help reduce inflammation in the body. Some anti-inflammatory agents that are available in supplement form include:

  • Fish oil (a rich source of omega-3 fatty acids)
  • Zinc
  • Turmeric/curcumin
  • Magnesium 
  • Selenium
  • Ginger 
  • Vitamins A, C, D, and E

Be sure to speak with your HCP before starting a new supplement, as some can interact with medications or other supplements you may be taking.

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Can you prevent inflammation?

Woman preparing a healthy salad packed with anti-inflammatory foods - greens, nuts and olive oil

Acute inflammation is a necessary and important function of your immune system. Chronic inflammation, however, can and should be avoided and addressed as much as possible.

While there’s no sure way to completely avoid chronic inflammation, implementing a few healthy lifestyle habits can minimize or prevent some harmful inflammatory responses.

To help avoid chronic inflammation, try:

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The bottom line on inflammation

Researchers are continuing to learn more about inflammation. There are still plenty of unknowns, but a few facts are clear:

  • Acute inflammation is an important and necessary function of the immune system.
  • Chronic inflammation (inflammation that persists for six weeks or longer) is harmful to health and can lead to inflammatory diseases.
  • Healthy lifestyle choices such as quitting smoking, exercising regularly, maintaining a healthy weight, and eating anti-inflammatory foods can help control inflammation. 

Check in with your HCP if you develop symptoms of chronic inflammation like fatigue or frequent infections. If you’ve been diagnosed with a condition associated with chronic inflammation, it’s important to attend all scheduled medical appointments, follow your HCP’s treatment guidance, and take steps to achieve a healthier lifestyle.

Inflammation is manageable for the most part. To learn more about inflammation and how you can prevent or control chronic inflammation, speak with your HCP.

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Featured inflammation articles

Topic page sources
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American College of Emergency Physicians. Fever. Accessed February 2, 2024.

Arthritis Foundation. 8 Food Ingredients That Can Cause Inflammation. Accessed Feb 1, 2024.

Arthritis Foundation. Imaging Tests for Rheumatoid Arthritis. Last updated April 28, 2022.   

Barcelos IP, Troxell RM, Graves JS. Mitochondrial Dysfunction and Multiple Sclerosis. Biology (Basel). 2019;8(2):37. Published 2019 May 11. 

Centers for Disease Control and Prevention. Dietary Guidelines for Alcohol. Last reviewed April 19, 2022.

Centers for Disease Control and Prevention. How Much Physical Activity Do Adults Need? Last reviewed June 2, 2022.  

Cerqueira É, Marinho DA, Neiva HP, Lourenço O. Inflammatory Effects of High and Moderate Intensity Exercise-A Systematic Review. Front Physiol. 2020;10:1550. Published 2020 Jan 9.  

Cleveland Clinic. Cytokines. Last reviewed January 3, 2023. 

Cleveland Clinic. Inflammation. Last reviewed December 20, 2023.

Deepak P, Axelrad JE, Ananthakrishnan AN. The role of the radiologist in determining disease severity in inflammatory bowel diseases. Gastrointest Endosc Clin N Am. 2019;29(3):447-470.

Godman H. Easy Ways to Keep Inflammation in Check. Harvard Health Publishing. Published February 1, 2023. 

Gotthardt M, Bleeker-Rovers C, Boerman O, Oyen W. Imaging of inflammation by PET, conventional scintigraphy, and other imaging techniques. Journal of Nuclear Medicine. Dec 2010, 51 (12) 1937-1949.

Hannoodee S, Nasuruddin D. Acute Inflammatory Response. StatPearls [Internet]. Last updated November 14, 2022.  

Harvard Health Publishing. How Acute Inflammation Turns Chronic. Published October 20, 2022.

Harvard Health Publishing. What is Inflammation? Published April 12, 2021.

National Institute of Environmental Health Sciences. Inflammation. Last reviewed September 13, 2023.  

Shmerling R. Should You Be Tested for Inflammation? Harvard Health Publishing. Published March 29, 2022.   

Szalay J. What is Inflammation? Live Science. Last updated December 8, 2023.

Tsai DH, Riediker M, Berchet A, et al. Effects of short- and long-term exposures to particulate matter on inflammatory marker levels in the general population. Environ Sci Pollut Res Int. 2019;26(19):19697-19704. 

Urpi-Sarda M, Casas R, Sacanella E, Corella D, Andrés-Lacueva C, Llorach R, Garrabou G, Cardellach F, Sala-Vila A, Ros E, et al. The 3-year effect of the Mediterranean diet intervention on inflammatory biomarkers related to cardiovascular disease. Biomedicines. 2021; 9(8):862.  

Watson S. All About Inflammation. Harvard Health Publishing. Published June 15, 2020.

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