Radiation poisoning, also known as radiation sickness, results from excessive exposure to ionizing radiation and can cause immediate, chronic, or delayed health effects. Symptoms depend on radiation dose and can include nausea, vomiting, diarrhea, hair loss, bleeding, and increased risk of infection, burns, and cancer. Treatment focuses on decontamination, supportive care, and potentially blocking internal radiation exposure or increasing white blood cell count to prevent infection. Non-ionizing radiation like visible light, microwaves, and radio waves can also cause health issues in high doses through tissue heating.