Poison is very effective against grass pokemon.
ground type Pokemon are super effective against poison type Pokemon.
ground and physic Pokemon are super effective against poison Pokemon
Psychic types are super effective against Poison types.
Ground and psychic type attacks are both super-effective against a poison type pokemon.
Poison and fighting
Ground type and psycic type
use ghost type on her phsycic and phsycic on her poison Pokemon
Psychic and ground type moves are super-effective against poison types I tried using fighting moves, and they were not very effective
Fighting and Poison. It is not very effective on Steel, and has no effect on Dark.
Garbodor is POISON type, so PSYCHIC or GROUND moves are effective.
Poison and Steel types are super effective against Fairy types.
In Generation 1 (Red, Blue, Yellow) Bug is super-effective against Poison, and Poison is super-effective against Bug. Weedle Kakuna Beedrill Venonat Venomoth