Potion Remove Event 
To use this event use the following import:
groovy
import net.minecraftforge.event.entity.living.PotionEvent.PotionRemoveEventSub-Classes 
This event extends the following events and can use all their methods and fields: 
PotionEvent, LivingEvent, EntityEvent
Methods 
groovy
net.minecraft.potion.Potion getPotion()groovy
net.minecraft.potion.PotionEffect getPotionEffect()