As the original host of the Venom symbiote, Eddie Brock was one of Spider-Man's greatest enemies. That changed when the symbiote was forcefully removed from Brock's body. The leftover Venom particles in his bloodstream were transformed, bonding to his white blood cells, becoming a symbiote unlike any before. Born again as Anti-Venom, he has all the strengths of a symbiote with none of the weaknesses, plus the ability to cure any disease or poison. As to whether Brock's hatred of Spider-Man has changed as well... that remains to be seen.