There are many warriors who use deadly toxins to overcome their foes, turning an otherwise minor injury into a mortal wound.
A model with the Poisoned Attacks special rule gets a +1 modifier to its To Wound rolls. For example, if they would normally need to roll a 4+ To Wound, a model with Poisoned Attacks only need to roll a 3+ To Wound. Armour saves are modified by the Strength of the attack as normal.
Unless otherwise stated, a model with this special rule has both Poisoned shooting and close combat attacks. Any spells cast by the model are unaffected, as are any special attacks or attacks made with magic weapons they might be wielding, whether they be shooting or close combat attacks.