Radioactive elements such as uranium and barium, release excess energy in the form of particles or waves. Alpha particles, beta particles, and gamma rays are types of radioactive emissions that can cause damage by interacting with the atoms that make up living cells. All types of radiation can cause damage to the body and lead to a condition known as radiation sickness. When radioactive particles or waves interact with atoms in your body they can knock off electrons that orbit the nucleus of that atom. This changes the way an atom normally functions, and forms ions (also known as free radicals). These ions have abnormal reactions with other atoms, such as the ones in a cell's genetic material, leading to mutations, and possibly, cancer. Exposure to high levels of radiation may lead to cell death, and consequently tissue or organ failure. A weakened immune system, often a sign of radiation sickness, results in increased number of infections. Initial symptoms are nausea, diarrhea, and weakness, sometimes followed by hair loss. Medication to reduce nausea and pain can be given, but only antibiotics and blood transfusions can help fight deadly infections and aid in a gradual recovery from radiation sickness.