▁Po ison ▁hem lock ▁( Con ium ▁mac ul atum ) ▁contains ▁highly ▁to xic ▁amounts ▁of ▁con i ine , ▁where ▁it ▁cont ributes ▁to ▁hem lock ' s ▁fet id ▁sm ell ; ▁in ▁addition , ▁it ▁contains ▁trace ▁amounts ▁of ▁other ▁similarly ▁poison ous ▁al kal oid s . ▁In gest ing ▁less ▁than ▁a ▁t enth ▁of ▁a ▁gram ▁of ▁con i ine ▁can ▁be ▁fatal ▁for ▁adult ▁humans ; ▁this ▁is ▁approximately ▁six ▁to ▁eight ▁hem lock ▁leaves . ▁The ▁se eds ▁and ▁roots ▁are ▁also ▁to xic , ▁more ▁so ▁than ▁the ▁leaves . ▁While ▁hem lock ▁to x icity ▁primarily ▁results ▁from ▁consumption , ▁poison ing ▁can ▁also ▁result ▁from ▁in hal ation , ▁and ▁from ▁skin ▁contact . ▁ ▁The ▁presence ▁of ▁hem lock ▁on ▁far ml and ▁is ▁an ▁issue ▁for ▁liv est ock ▁far mers ▁because ▁animals ▁will ▁eat ▁it ▁if ▁they ▁are ▁not ▁well ▁fed ▁or ▁the ▁hem lock ▁is ▁mixed ▁in ▁with ▁past ure ▁grass . ▁Farm ers ▁also ▁need ▁to ▁be ▁careful ▁that ▁the ▁hay ▁fed ▁to ▁animals ▁does ▁not ▁contain ▁hem lock . ▁Po ison ▁hem lock ▁is ▁most ▁poison ous ▁in ▁the ▁spring ▁when ▁the ▁concentration ▁of ▁ γ - con ic iene ▁( the ▁prec ursor ▁to ▁other ▁to x ins ) ▁is ▁at ▁its ▁peak . ▁ ▁Po ison ▁hem lock ▁grows ▁quite ▁tall , ▁reaching ▁height s ▁of ▁up ▁to ▁twelve ▁feet . ▁The ▁st alk ▁of ▁hem lock ▁is ▁green ▁with ▁pur ple ▁sp