I haven't updated in a while, but for my Poison Challenge, I am in front of the door leading to the Elite Four. I will recall the last three gyms.
Sabrina: The gym was difficult, as all my pokemon were weak to Psychic, and I had forgotten Ghost did not work on Psychic by the time I had a Haunter, but though the gym trainers were all hard, Sabrina was quite easy. She kept using X Defend and the sort, and switching out, so she took out none of my Pokemon.
Blaine: With my new Tentacruel, named Jelly, I defeated all his Pokemon with my newly aquired Surf. The wholoe Gym went like that. While I was in Cinnabar, I caught a Weezing and a Muk who made their way into my party.
Giovanni: He was a little difficult at first, as I was using Nidoking, but after he got defeated I brang out Tentacruel who sweeped his Ground pokemon. Arbok helped with his Rhydon very well.
Team:
Nido/Nidoking Lv 51
Horn Drill
Double Kick
Hoorn Attack
Strength
Jelly/Tentacruel Lv 47
Wrap
Cut
Ice Beam
Surf
Blorgh/Muk Lv 46
Disable
Fire Blast
Minimize
Sludge
Boo/Haunter Lv 47
Psychic
Confuse Ray
Psywave
Hypnosis
Smoakr/Weezing Lv 47
Explosion
Smog
Sludge
Smokescreen
Kobra/Arbok Lv 48
Screech
Earthquake
Double-Edge
Acid