Teardrop!
Wolfsbane's benefits to a werewolf can never be compared to the numerous adverse effects it has on them. It is rather one of their worst nightmares.
Rogues usually dilute it to weaken themselves when they realize they may get out of hand and hurt people wantonly. Losing control of oneself would mean that the Dark-Dawn Pack would locate them without any difficulty.
Even in that case, the wolfsbane is diluted in water. A small pinch could be diluted with as much as a liter of water. Only a little portion is needed to acquire the necessary result.
Meanwhile, when wolfsbane touches a wolf's body, it causes the spot to burn and spread rapidly. Healing from such a burn is extremely slow, even though wolves have regenerative abilities.
Wolves in Dark-Dawn Avenue, however, have never needed to use Wolfsbane, as the full moon doesn't have any adverse effect on them.