Radiation sickness, also called acute radiation syndrome or radiation poisoning, is damage to the body caused by a large dose of radiation often received over a short period of time. The amount of radiation absorbed by the body determines how sick the patient will be. Common exposures to low-dose radiation, such as X-ray or CT examinations, do not cause radiation sickness. Also, even tough radiation sickness is serious and often fatal, it is rare.



Radiation sickness is usually only experienced by people who are exposed to 300 or more times the average yearly dose of background radiation. How severe these problems are and when they show up depends on how much radiation the person was exposed to. It also depends on whether the person was exposed to radiation over a short or long period of time. The symptoms can be classified as early and late symptoms. The early ones appear within hours after the exposure, whilst later symptoms appear within weeks. A person exposed to extremely high doses of radiation may have:

  • A drop in blood cell counts;
  • Hair loss;
  • Nausea;
  • Vomiting;
  • Diarrhea;
  • Skin burns;
  • An eventual increased risk for blood and thyroid cancers; and
  • Eventual death as a result of organ failure.



Radiation sickness occurs when high-energy radiation damages or destroys certain cells in the body. Regions of the body most vulnerable to high-energy radiation are cells in the lining of the intestinal tract, including the stomach, and the blood cell-producing cells of bone marrow. Radiation sickness is caused by the following events:

  • Accidental exposure to high doses of radiation such as a nuclear power plant accidents;
  • Exposure to excessive radiation for medical treatments.

Possible sources of high-dose radiation include the following:

  • An accident at a nuclear industrial facility;
  • An attack on a nuclear industrial facility;
  • Detonation of a small radioactive device;
  • Detonation of a nuclear weapon or conventional explosive device that disperses radioactive material



Radiation exposure that causes immediate radiation sickness significantly increases a person's risk of developing leukemia or cancer later in life. Having radiation sickness could also contribute to both short-term and long-term mental health problems, such as grief, fear and anxiety about experiencing a radioactive accident, dealing with the uncertainty of a mysterious and potentially fatal illness or worrying about the eventual risk of cancer due to the radiation.



In the event of a radiation emergency, there are certain precautions a person can take, like:

  • Avoiding unnecessary exposure to radiation;
  • Sheltering in one place;
  • Evacuation;
  • Persons working in radiation hazard areas should wear badges to measure their exposure levels;
  • Protective shields should always be placed over the parts of the body not being treated or studied during x-ray imaging tests or radiation therapy.