Exposure to large amounts of radioactive cesium can damage cells in your body from the radiation. You might also experience acute radiation syndrome

Why is cesium so dangerous?

Final Summary. Cesium-137 is an especially dangerous fission product because of its high yield during fission, moderate half-life, high-energy decay pathway, and chemical reactivity. Because of these properties, cesium-137 is a major contributor to the total radiation released during nuclear accidents.

What happens if you touch cesium?

When contact with radioactive cesium occurs, which is highly unlikely, a person can experience cell damage due to radiation of the cesium particles. Due to this, effects such as nausea, vomiting, diarrhoea and bleeding may occur. When the exposure lasts a long time people may even lose consciousness.