Radiation poisoning

Radiation sickness was an illness caused by exposure to excess radiation. Coughing was one of the first signs of the illness. (AUDIO: Protect and Survive)

When the First Doctor, Susan Foreman and Ian Chesterton discovered, through the use of a Geiger counter, that there was excess radiation on Skaro, they deduced that it was causing radiation sickness. In that particular case, the effects of the disease included a jungle being turned to stone, soil becoming barren, and a feeling of sickness between the three. (TV: The Daleks)

On Oseidon, the Fourth Doctor and Sarah Jane Smith speculated that the soldier they saw going over a cliff was suffering from radiation sickness. (TV: The Android Invasion)

On Terminus, Bor suffered from radiation sickness. (TV: Terminus)