Nuclear radiation effects on humans 

Cause and effects

• nausea
• vomiting
• headache
• some loss of white blood cells

   

   Doses of 300 rems or more cause temporary hair loss, but also more significant internal harm, including damage to nerve cells and the cells that line the digestive tract. Severe loss of white blood cells, which are the body's main defense against infection, makes radiation victims highly vulnerable to disease. Radiation also reduces production of blood platelets, which aid blood clotting, so victims of radiation sickness are also vulnerable to hemorrhaging. Half of all people exposed to 450 rems die, and doses of 800 rems or more are always fatal. Besides the symptoms mentioned above, these people also suffer from fever and diarrhea. As of yet, there is no effective treatment--so death occurs within two to fourteen days.

   In time, for survivors, diseases such as leukemia (cancer of the blood), lung cancer, thyroid cancer, breast cancer, and cancers of other organs can appear due to the radiation received.

http://library.thinkquest.org/3471/radiation_effects_body.html