Poisoned
From FOnline: 2238 Wiki
Your character has been poisoned. Poison will do damage over peroid of time, until cured or it passes from your system.
More information
Character was most likely bitten by one of poisonous creatures in wasteland (like common Radscorpion). It will recive small amount of damage over time until poison will be expelled out of body. Rate of reciving damage depends of amount of poison inside body.
High poison resistance reduces time of character being poisoned.
Poison can be cured with antidote.
Warning
Character below 0 HPs that recives poison damage shall die even if it's HP isn't -20.