Eseroline is a pyrroloindole that is 1,2,3,3a,8,8a-hexahydropyrrolo[2,3-b]indole substituted by methyl groups at positions 1, 3a and 8 and a hydroxy group at position 5. It is a metabolite of physostigmine and causes neuronal cell death by a mechanism involving loss of cell ATP. It has a role as an opioid analgesic and a human xenobiotic metabolite. It is a member of phenols and a pyrroloindole.