Radiation can be the No.1 freaking bad effect in Minecraft(with IC2), because it can't even be removed by the /effect player remove command, and once you are affected, the only thing you can do is to wait for death :( Have you been driven up the wall when you find you got a radiation effect and soon died when you were just walking without protective clothing? This passage may be useful. YOU NEED: - to be OP in multiplayers or allow cheats in singleplayer - NBTEDIT installed in your client (there's no need to install it on server) - a brave heart

First of all, you should know that the radiation effect id is 24, which is not defined in the vanilla minecraft 1.7.10 (or earlier versions). Therefore it cannot be given to players with commands like this:

{CustomPotionEffects:[{Id:24,Amplifier:127,Duration:300}]}

That's why I recommend to use NBTEDIT. There is a common principle in minecraft potion effects that low-level effects will ALWAYS be replaced by the same high-level ones, ignoring the duration. So my radiation-clearing potion is simply a potion of radiation that has a level of 127 but duration of 0.

Here we go and make it.

First you should get a commmand block:

/give player command_block 1

Then give yourself some potions:

/give @p potion 64 0 {CustomPotionEffects:[{Id:1,Amplifier:127,Duration:300}],display:{Name:"Remove Radiation!"}}

Put this potion into a chest, move your crosshair on the chest, and type:

/nbtedit

Left-click the triangles to expand the dendrogram.

ROOT:(TagCompound) → Items:(TagList) → (TagCompound) → tag:(TagCompound) → CustomPotionEffects:(TagList) → (TagCompound)

And edit the tag 'Id' and 'Duration'

Id:24, Duration:0

Save & quit!

Now when you got a radiation, drink it and you will recover.

PS: You cannot make a splash potion in this way, because the effect will disappear before you get the effect.