Arch Cure has no problem curing even Lvl 5 Poison, even at just GM Magery. At 0% EP, Greater Cure Pots have a 45% chance to cure DP (Lvl 4), and a 25% chance to cure Lethal (Lvl 5). This jumps to 67% and 37% with the cap of 50% EP. Vampire Form grants immunity to up to Greater Poison, resistance to Deadly Poison, and is overpowered by Lethal Poison. Same with Orange Petals (DP has a 25% chance to overpower Petal resistance). Both Vamp Form and Orange Petals allow the Poison to be applied to you (which interferes with non-leech/Regen healing), but as soon as the poison tries to tick for damage, it can be resisted and removed. Unicorn Form from Ninjitsu grants complete Poison immunity up to Lvl 5, the Poison will not even apply to you.
Creatures with high Poisoning and high Magery can apply DP to you with the Poison spell when they're within 3 tiles of you. Without Magery, Poisoning creatures have to be within melee range of you to apply DP or Lethal. The only exception to this, is creatures with Poison Breath, such as Dimetrosaurs, Yamandons and Serado the Awakened. They can DP-Lethal you if you're within 9 tiles of them.
So as a Tamer, that usually starts off at range from monsters initially, and has a pet to tank for you, Orange Petals work great against everything but Poison Breath, which not many creatures have.