All of my dwellers have red on their health bar! How do I solve this? Because each time I use a radaway it comes back instantly! Help ASAP!

If you mean instantly, like the second you use it, then I don't know. If you mean half a minute later, then it could be that all your dwellers are really sad. If it is because they are sad try making sure they have food and water, or assign them to the rooms they are most skilled at.

Do your dwellers have enough water? If they're short on water they'll suffer from radiation sickness.

As PipPipPipPip said. Your dwellers demand food and water, your rooms demand energy:

- If there's not enough energy, the rooms farther away from an energy generation room will shutdown, until there's enough output to sustain the rest.

- If there's not enough food, your dwellers will take health damage.

- It there's not enough water, your dwellers will take sustained radiation damage.

So, if your water bar is on the red zone you have not enough water to sustain your dweller population (or simply you forgot to gather). So, either build more rroms, upgrade existing ones, or place more dwellers so resource rooms fill faster.

I increased my water and food supply and now everyone is happy and no radiation! Thanks everyone!