Radiation poisoning, also called "radiation sickness", is damage to the (human or other animal) body from excessive exposure to ionizing radiation. The term is generally used to refer to acute problems caused by a large dosage of radiation in a short period. Many of the symptoms of radiation poisoning occurs as ionizing radiation interferes with cell division. This especially causes problems with rapidly dividing cells, such as intestinal cells.
The symptoms of radiation poisoning include skin burns, fainting, fatigue, diarrhea, hair loss, and at extremely high dosages, death. An extremely high dose of radiation, such as 10,000 rads in a short period will cause unconsciousness and death as nerve cells are destroyed. A smaller dosage will cause immediate illness of fainting and fatigue, but the victim will appear to recover, only to die within days as the rapidly dividing intestinal cells fail. Exposure to 400 roentgens in a short period is fatal within a few days in approximately half the cases. If the victim survives the next few weeks, he or she is likely to recover, but will face an increased chance of cancer.
Chronic exposure to radiation can lead to leukemia and other cancers. Ironically, the ability of radiation to disturb cell division is also used to treat cancer.
Radiation poisoning can result from accidental exposure to natural or industrial radiation sources. People working with radioactive materials often wear film "badges" to monitor their total exposure to radiation.
Radiation poisoning caused illness and death after the bombings of Hiroshima and Nagasaki and downwind of the atmospheric testing of the '50s, and was a major concern after the Chernobyl reactor accident.
See also Radiation.