The Aconitum Seeds can be obtained as a Purchasable Item through purchase with 5 × Ancient Amber and comes in packs of 4. They can also be obtained from fully grown Monkshood Flowers. The item will be returned to the inventory when destroyed or lost.
Aconitum Seeds can be planted in a Planter to grow Monkshood Flowers. Monkshood Flowers produce Purple-colored Potent Dust, Rare Flowers, and an additional Aconitum Seed.
The seeds are essentially a very strong Narcoberry that have the property of rejuvenating Stamina.
It isn't recommended for PvP unless your Fortitude is leveled by at least 16+ as this will reduce the Torpor they inflict to under 10 instead of the full 20. If you have high Fortitude then it might be worth it as it gives 100 Stamina.
The Torpor produced from consuming or force-feeding these seeds is 3x as much torpor as a Narcoberry.
A player with 16 or more points leveled into Fortitude will gain only half of the Torpor.
Seeds can be regrown and farmed for a more potent form of Narcoberries.
When the Monkshood Flowers grow, you can dye them either with a Paintbrush or Spray Painter and the Potent Dust produced will reflect the color of the flower.
Ancient Amber and comes in packs of 4. They can also be obtained from fully grown Monkshood Flowers. The item will be returned to the inventory when destroyed or lost.
Potent Dust, 
Rare Flowers, and an additional Aconitum Seed.
Narcoberry that have the property of rejuvenating 
Stamina.
Fortitude is leveled by at least 16+ as this will reduce the 
Torpor they inflict to under 10 instead of the full 20. If you have high 
Paintbrush or 
Spray Painter and the 
Consumables
Pharmaceuticals