Pepper spray is an aerosol spray that contains an inflammatory compound called capsaicin. It causes burning, pain, and tears when it comes into contact with a person’s eyes.

Pepper sprays are available commercially for personal protection against assailants. Law enforcement agencies in the United States use pepper spray during policing, crowd control, and to suppress protests and demonstrations. The use of pepper spray remains controversial.

This article examines what is in pepper spray, how dangerous it is, and possible ways to treat pepper spray exposure.

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Pepper spray is a lacrimator, meaning that it stimulates the eyes to produce tears. It typically comes in an aerosol or spray bottle.

The main component of pepper spray is an oil known as oleoresin capsicum. This oil comes from plants in the genus Capsicum, which includes chili peppers.

The active ingredient in pepper spray is capsaicin, the same chemical that adds the characteristic heat to chili peppers. Pepper spray contains much higher concentrations of capsaicin than chili peppers.

Capsicum oil also forms the basis of bear spray, an aerosol designed to protect humans who encounter a bear.

Pepper spray has a very high score on the Scoville heat units (SHU) scale, which measures the “heat” of peppers. On the Scoville scale:

  • a bell pepper measures 0 SHU
  • a jalapeño pepper scores around 2,500–5,000 SHU
  • pepper spray that law enforcement officers use measures between 500,000 and 2 million SHU, with some brands measuring 5.3 million SHU

The capsaicin concentration of most pepper spray that law enforcement agents use is 5–10%. A higher concentration results in longer lasting effects.

Pepper spray use is controversial, particularly when members of law enforcement units use it against civilian protestors.

The Chemical Weapons Convention ban the use of riot control measures such as pepper spray and tear gas in warfare. However, law enforcement officers use pepper spray and tear gas to disperse crowds and suppress protests.

Civilians can buy pepper spray over the counter for self-defense, though some U.S. states restrict its sales.

When pepper spray comes into contact with a person’s eyes, it causes immediate eye closure, acute eye pain, and temporary blindness. Some people describe a bubbling or boiling sensation and severe discomfort.

Pepper spray can also have the following effects:

  • a dry cough or wheezing
  • shortness of breath or an inability to breathe properly
  • throat burning
  • chest pain
  • gagging
  • a runny nose
  • gasping for air
  • panic
  • an inability to speak
  • dizziness
  • loss of consciousness
  • rashes, blisters, or burns on contact with the skin

People report scratches to the eyeball, or corneal abrasions, in about 10% of cases. Such scratches are temporary and may result from a person rubbing their eyes.

While painful, the symptoms are self-limiting in most cases. They tend to resolve on their own within 30 minutes and usually do not require medical treatment.

A cough or shortness of breath can persist, especially in people with lung disorders. People with conditions such as asthma or chronic obstructive pulmonary disease (COPD) may experience more severe breathing effects.

In rare cases, pepper spray can cause cyanosis, a bluish discoloration of the skin that indicates a lack of blood flow and oxygen.

Complications are uncommon, but serious exposure can lead to more severe injuries to the eyes, skin, and respiratory tract.

The Police Policy Studies Council recommend that you bring an exposed person to the hospital if their symptoms persist for longer than 45 minutes or the person requests it.

The group recommend calling emergency services if someone shows signs of distress after exposure to pepper spray, such as:

  • a loss of consciousness
  • difficulty breathing
  • chest pain

Death is rare, but several reports have implicated pepper spray in fatal outcomes in people with asthma.

There is no immediate cure for pepper spray exposure, but people can often reduce the duration and intensity of the symptoms by:

  • moving into an area with fresh air, if possible
  • flushing the affected area with lots of water to wash away the contaminants
  • avoiding using soap around the eyes as it is an irritant
  • removing clothing that may have come into contact with the spray to decontaminate and prevent re-contamination.
  • avoiding touching the affected area, as it is easy to spread the oil-based solution to other areas of the body by doing so
  • blinking the eyes rapidly to help flush out the chemical

Popular strategies for removing pepper spray include baby shampoo, milk, antacids, and lidocaine. However, a 2008 study comparing these strategies found no evidence that they were more effective than water.

A randomized controlled trial from 2018 also reported no difference between baby shampoo and water alone in relieving the effects of tear gas and pepper spray.

Emergency responders may use wipes and saline solutions to help relieve symptoms of pepper spray exposure.

A saline solution called diphoterine is an effective emergency treatment for various chemicals in contact with the eyes or skin, though research has not shown it to remove pepper spray effectively.

In most cases, pepper spray symptoms resolve within 10–30 minutes and do not require medical care.

Since the early 1980s, law enforcement agents in the U.S. have used pepper spray in policing and crowd control.

When pepper spray hits a person’s face, it temporarily blinds them and causes severe pain and discomfort. This allows police to subdue and arrest people, disperse protestors, and suppress demonstrations.

Police use of pepper spray remains controversial. During the 2020 Black Lives Matter protests, Amnesty International raised serious concerns that law enforcement had violated protestors’ human rights through unnecessary and sometimes excessive force, including the use of pepper spray.

These concerns center around the use of pepper spray, tear gas, and other tactics as “a first resort tactic against peaceful protestors rather than as a response to any sort of actual threat or violence.”

Amnesty International’s report documented 21 instances of unlawful police use of pepper spray across 15 states and in the District of Columbia between May and June, along with 89 uses of tear gas.

In addition, a 2016 study by Harvard University researchers found that police in the U.S. are more likely to use pepper spray on Black people than white people. This is just one of the serious concerns about systemic racism and racial discrimination within law enforcement.

Research has looked into the relative benefits and risks of using pepper spray for crowd control. A 2017 review looked at the health effects of using chemical irritants in this context in 31 studies across 11 countries.

The researchers concluded that, while pepper spray can have limited use in crowd control, there is a “significant potential for misuse, leading to unnecessary morbidity and mortality.”

Pepper spray is known as a “nonlethal weapon,” or a weapon that cannot kill people. While death is rare, reports have linked several deaths with the use of pepper spray.

In 2003, a Department of Justice report on an investigation into 63 deaths of people in custody found that pepper spray directly contributed to the deaths of two people. The police had used pepper spray in the arrest of all the individuals.

The report attributed the cause of these deaths to the pepper spray, citing preexisting asthma as a contributing factor. Causes of death for other study subjects were drug use, disease, positional asphyxia, or a combination of factors.

The same report concluded the following:

“Pepper spray inhalation alone does not pose a significant risk for respiratory compromise or asphyxiation, even when combined with positional restraint.”

Pepper spray is a chemical that law enforcement and civilians are legally allowed to use for defense. It can be dangerous, and its use is controversial, especially when agents use it against civilian protesters.