Anti-radiation pills were drugs to combat the effects of radiation. The Fourth Doctor gave Romana II some of the pills before venturing out onto Skaro as the levels of radiation were quite high. (TV: Destiny of the Daleks)
The Tenth Doctor had, among other things, anti-radiation pills in his pockets during his visit to Arcopolis. (PROSE: The Eyeless)
The Eleventh Doctor handed out anti-radiation pills to the villagers of Klimtenburg to protect them from Hapthoid radiation poisoning spread by the reactor of a crashed Cyberman ship. (PROSE: Plague of the Cybermen)