Rad Tolerance

 is a perk added to Fallout 3 with the Broken Steel DLC.

With this perk, you suffer no effects from minor radiation poisoning. This perk has no effect on future radiation levels. For example, Advance Radiation Poisoning still causes -2 END and -1 AGI. All this perk does it make Minor Radiation Poisoning not cause -1 END anymore. Basically, unless your END score is already at 10, then using Intense Training on END would be more powerful than this perk. END lost from poisoning has no effect on HP, so this perk is of dubious use, if any.