Cyanide Poisoning

Facts and Definition of Cyanide Poisoning

Learn cyanide poisoning symptoms, treatment, and multiple causes.
Learn cyanide poisoning symptoms, treatment, and multiple causes.
  • Cyanide is a rare, but potentially deadly poison. It works by making the body unable to use life-sustaining oxygen. Cyanide compounds that can be poisonous include hydrogen cyanide gas, and the crystalline solids, potassium cyanide and sodium cyanide.
  • Common sources of cyanide poisoning include
    • smoke inhalation from fires,
    • industries that use cyanide (photography, chemical research, synthetic plastics, metal processing, and electroplating),
    • plants (such as apricot pits and a type of potato called cassava),
    • the cancer treatment laetrile, and
    • cigarette smoke.
  • Signs and symptoms of cyanide poisoning can be difficult to detect and include
    1. general weakness,
    2. confusion,
    3. bizarre behavior,
    4. excessive sleepiness,
    5. coma,
    6. shortness of breath,
    7. headache,
    8. dizziness,
    9. vomiting,
    10. abdominal pain, and
    11. seizures.
  • The skin may be unusually pink or cherry-red, breathing may be fast, and heartbeat may be slow or fast.
  • An acute ingestion of cyanide will have a dramatic, rapid onset, immediately affecting the heart and causing sudden collapse, a seizure, or coma. Chronic poisoning from ingestion or the environment has a more gradual onset.
  • The setting may be more of a clue to whether a person has experienced cyanide poisoning than the symptoms.
  • If you or someone you know has ingested, inhaled or been exposed to cyanide, and you or the person has signs or symptoms, such as weakness, dizziness, trouble breathing, confusion, or seizure, you must immediately call an ambulance, the emergency response system in your area, or a poison control center. In the United States, the National Poison Control Center contact number is 1-800-222-1222.
  • Cyanide poisoning cannot be treated at home. Immediate medical attention is always required.
  • Cyanide poisoning can be treatable when it is done promptly. Clothing that may contain traces of cyanide will be removed, and a Cyanide Antidote Kit (CAK) or hydroxocobalamin (Cyanokit) may be used.
  • Cyanide poisoning may be prevented in many cases with strict work safety regulations, home fire precautions, and childproofing of the home.

What Are the Signs and Symptoms of Cyanide Poisoning?

Detection of cyanide poisoning can be difficult. The effects of cyanide ingestion are very similar to the effects of suffocation. The mechanism of toxicity occurs because cyanide stops the cells of the body from being able to use oxygen, which all cells need to survive.

  • The symptoms of cyanide poisoning are similar to those experienced when hiking or climbing at high altitudes, and include:
  • Typically, acute cyanide ingestion will have a dramatic, rapid onset, immediately affecting the heart and causing sudden collapse. It also can immediately affect the brain and cause a seizure or coma.
  • Chronic cyanide poisoning (over a long period of time) from ingestion or environmental poisoning will have a more gradual onset, and symptoms may include:
  • The skin of a cyanide-poisoned person can sometimes be unusually pink or cherry-red because oxygen will stay in the blood and not get into the cells. The person may also breathe very fast and have either a very fast or very slow heartbeat. Sometimes the person's breath can smell like bitter almonds, though this can be difficult to detect.
  • Perhaps most important is the environment, rather than the signs or symptoms.
    • A person who works in a laboratory or plastics factory has a higher risk of cyanide poisoning.
    • Home, RV, boat, or building fires always include the additional concern of cyanide exposure.
    • If you know someone has been depressed or has substance abuse problems and you find him or her with any of the signs or symptoms of cyanide poisoning, then a suicide attempt is possible.

What Are Common Sources and Causes of Cyanide Poisoning?

Common sources of cyanide poisoning include:

  • Fires: Smoke inhalation during the burning of common substances such as rubber, plastic, and silk can create cyanide fumes and cause cyanide poisoning.
  • Photography, chemical research, synthetic plastics and fibers, metal processing, fumigation and pesticides, mining, and electroplating industries use hydrogen cyanide. Potassium cyanide is used in gold and silver extraction, chemical analysis, to make other chemicals, and as an insecticide.
  • Plants: Mostly from the family Rosaceae, seeds and pits from plants such as apricot, bitter almond, cherry laurel, plum, peach, pear, and apple contain cyanogenic glycosides. A type of potato called cassava can also cause cyanide poisoning. Fortunately, only chronic or massive ingestion of any of these plants or pits can cause serious cyanide poisoning.
  • Laetrile, a compound that contains amygdalin (a chemical found in the pits of raw fruits, nuts, and plants) has been purported as a cancer treatment worldwide. One of the side effects of laetrile is cyanide poisoning. The Food and Drug Administration (FDA) has not approved laetrile as a cancer treatment in the United States. The drug is also made and used as a cancer treatment in Mexico under the name "laetrile/amygdalin."
  • Certain chemicals, after ingestion, can be converted by the body into cyanide and cause cyanide poisoning. Most of these chemicals have been removed from the market, but some old artificial nail polish removers, solvents, and plastics manufacturing solutions can contain these substances.
  • Cigarette smoke is the most common source of cyanide exposure for most people. Cyanide is naturally found in tobacco, and smokers can have more than 2.5 times the mean whole blood cyanide level of nonsmokers, though this is generally not enough to cause poisoning.

Those most at risk of cyanide poisoning are those who work in industries that use this chemical and people who intentionally try to kill themselves. Those who attempt suicide by using cyanide pills or capsules may believe it is a quick and painless death, however, cyanide burns the stomach and prevents the body from using oxygen, causing a painful death.

For most people, cyanide only causes poisoning if a fire occurs or if some of the compounds mentioned above are accidentally ingested.

When to Seek Medical Care for Cyanide Poisoning

If you or someone you know has ingested, inhaled or been exposed to cyanide, and you or the person has signs or symptoms, such as weakness, dizziness, trouble breathing, confusion, or seizure, you must immediately call an ambulance, the emergency response system in your area, or a poison control center. In the United States, the National Poison Control Center contact number is 1-800-222-1222.

It can be very difficult to determine if someone has been exposed to cyanide. If you are in doubt, it is always best to contact a health care professional. If the victim is not in danger, contact your local poison center for instructions.

  • In the United States, you can find your local poison center at the American Association of Poison Control Centers. The U.S. National Poison Control Center phone number is 1-800-222-1222. This number is routed to the poison control center that serves your area. Place the telephone number (along with police, fire, and 911 or equivalent) near your home phones.
  • Calling the National Poison Control Center, or the poison control center in your area would be appropriate for example, if the potential victim accidentally swallowed a few apricot pits or breathed in a little too much smoke during a bonfire.
  • If the victim is unconscious, collapses, has a seizure, is acting confused, or feels short of breath this is a medical emergency, and your local emergency response system, 911, or an ambulance should be contacted immediately.
  • In most cases, calling 911 and waiting for the ambulance to arrive is the best thing to do.
  • Do not induce vomiting or give syrup of Ipecac.
    • Ipecac was formerly used to induce vomiting in poisoned patients where there was a chance to get the toxin out of the body. Several advisory bodies such as the American Association of Poison Control Centers and the American Academy of Pediatrics have recommended that Ipecac NOT be used and that it should not even be kept in the household. For more information on this subject go to:
  • Do not give activated charcoal at home. Allow medical personnel to decide if this treatment is appropriate.
  • The poison control center will provide instructions in regard to what action to take.

How Is Cyanide Poisoning Diagnosed?

Treatment in a hospital's emergency department will depend on the victim's level of illness.

  • Cyanide poisoning is a treatable condition, and it can be cured if detected quickly and treatment is started immediately. Most people die because the diagnosis is not made quickly enough, or it is not considered from the start. Cyanide poisoning is rare, so the treating physician should be alerted of the possibility. This may be one of the most important things you can do to help the victim.
  • If you are the rescuer, you will be asked questions about what happened to the victim. You will be asked if there were any bottles lying around, if the victim had any medical or psychiatric problems, and other details. Stay calm and answer the questions, because this is vital information necessary to care for the injured person.
  • Blood tests, X-rays, and other procedures will be necessary to try to determine if cyanide poisoning has occurred, how bad the poisoning is, or if some other type of poisoning has occurred.
  • The diagnostic test to detect cyanide takes hours to days to perform. Thus, the doctors will rely on a combination of what you tell them, what the victim looks like, and supporting laboratory data to decide the likelihood of actual cyanide exposure.
  • A prototype diagnostic test for the detection of cyanide has been developed at South Dakota State University that can detect it within 70 seconds. More study is needed to determine accuracy and to develop a smaller device with replaceable cartridges.

Is There an Antidote Treatment for Cyanide Poisoning?

Depending on how sick the patient is, treatment will vary.

  • If the patient is completely unconscious, all attempts will be made to save the person's life. A variety of invasive measures may need to be performed on the patient in order to closely monitor and evaluate the person.
  • If the patient's condition is not grave, he or she will need a thorough investigation. Typically, the patient's clothes will be removed because leftover cyanide on clothing can continue to poison both the patient and those providing care.
  • A Cyanide Antidote Kit (CAK) or Hydroxocobalamin (Cyanokit) may be used if a strong suspicion for cyanide poisoning exists. Although not a 100% successful cure, these antidotes can often prevent the cyanide from further poisoning the victim.
  • Dicobalt edetate is an intravenous chelator of cyanide (helps remove cyanide from the body) used in the United Kingdom. It is can have severe side effects including seizures, anaphylaxis, low blood pressure, and abnormal heartbeat. It is used only when a diagnosis of cyanide poisoning is nearly certain and alternative treatments are unavailable.
  • If the person has carbon monoxide poisoning as well, hyperbaric oxygen therapy may be used if available. This requires placing the person in a special chamber that will give an extremely high amount of oxygen.
  • Usually the local poison control center or poison specialist (toxicologist) will be notified about the victim. Their assistance will help to determine the patient's care.
  • If it is determined that the risk of actual cyanide ingestion is very low, the patient may be monitored for a few hours. If the patient appears well enough, he or she may be sent home with careful instructions to return immediately if any of the previous signs or symptoms develop.
  • If a patient has had a significant cyanide exposure, has preexisting illnesses, or has an uncertain diagnosis and is too ill to go home, the person will be admitted to the hospital for further treatment and observation.

Can Cyanide Poisoning Be Treated at Home?

Cyanide poisoning cannot be treated at home. Immediate medical attention is always required.

  • If there is a fire, make sure you or others are not in danger from smoke or fumes.
  • Then call 911 or have someone else call 911. Speak calmly, and clearly state your address, name, and what has happened. As with all first aid treatment, be sure no one is in danger.
  • Check the area for fires, potentially poisonous fumes, smoke, and spilled chemicals. The victim's clothes and body can also be sources of danger if the cyanide is still on the victim.
  • If you or others near the victim feel that CPR is necessary, begin the assessment, but do not perform mouth-to-mouth resuscitation on the victim without barrier protection because the person providing CPR can absorb cyanide in this manner. CPR can be performed without mouth-to-mouth contact if a protection barrier is not available. If you do not know CPR, lay the person on the floor, preferably on his or her left side.
  • Look around for pill bottles, chemical bottles, or open fires, because these could be responsible for the poisoning and knowledge of these will help the medical team treat the victim.

Do I Need to Follow Up With My Doctor After Suffering From Cyanide Poisoning?

If the patient of cyanide poisoning is sent home, reexamination is recommended within 24 hours to assure nothing more serious develops during this time. If the patient is admitted to the hospital, when he or she leaves, individualized instructions will be given regarding follow-up.

Usually, it is recommended that the patient follow up with a neurologist or neuropsychiatrist (doctors who specialize in the mind, brain, and nerves) to monitor for potential delayed-onset problems with the brain or nervous system.

How Can Cyanide Poisoning Be Prevented?

  • Childproofing a home is essential for all households with young children, particularly if a parent or caregiver works in an industry that uses cyanide.
  • Strict work safety regulations must be followed to prevent occupational exposure. Employees must leave all chemicals in the laboratory or factory. Cyanide can be absorbed through the lungs, stomach, and skin.
  • Standard home fire precautions should be taken, including installation of smoke detectors, avoidance of space heaters and halogen lamps, and not smoking in bed.
  • If you are concerned that someone you know is depressed or has voiced suicidal thoughts, take this as a serious true cry for help and encourage this person to seek medical care immediately. Every community has a suicide prevention system or hotline that can help arrange psychiatric care, or call the National Suicide Prevention Lifeline at 1-800-273-TALK; 1-800-273-8255.

What Is the Prognosis for a Person Who Has Suffered From Cyanide Poisoning?

It is difficult to determine prognosis with cyanide exposure, but reliable predictors of outcome are how sick the patient was when first brought to the hospital, and how quickly he or she was brought to the hospital. If timely medical attention is given and the patient is still awake and talking, the prognosis is usually very good. There is a chance that delayed neurological problems may develop.

poison, poisoning, symptoms, poisonous, poison control

Poisoning Symptoms

Seek medical help if you see the following signs

Signs and symptoms of poisoning are so wide and variable that there is no easy way to classify them, but they may include:

  • Enlarged or small pupils
  • Excessive drooling
  • Racing heart
  • Pain
  • Hyperactivity
  • Confusion
  • Drowsiness
  • Dry skin
  • Dry mouth
Centers for Disease Control and Prevention. "HYDROGEN CYANIDE (AC) : Systemic Agent." Updated: May 12, 2011. <>

Desai, S., et al. "Cyanide Poisoning." UpToDate. Updated: March 25, 2019.

Leybell, I., MD. "Cyanide Toxicity." Medscape. Updated: Jan 02, 2018.

NOAA; Cameo Chemicals. "Potassium Cyanide."

South Dakota State University, Office of Technology Transfer & Commercialization. "T-00229: A Field-Portable Sensor for the Rapid Diagnosis of Cyanide Poisoning."

The EXIT euthanasia blog. "An unusual death by cyanide." Posted: Jul 12, 2012.