ABSTRACT
Toxic Principle and Mechanism of Action Several pyridine alkaloids including the highly toxic gamma-coniceine, the precursor of coniine, and N-methylconiine are predominantly responsible for the central nervous system depression and teratogenic effects seen in many species of animal eating the roots, immature vegetation, and especially the seeds.1,2 Pregnant cattle, sheep, and pigs consuming poison hemlock in the first trimester of pregnancy produce fetuses with cleft palates and variable degrees of limb deformities.3,4 The alkaloid effects on the central nervous system are poorly understood, but are assumed to be similar to that of nicotine. The alkaloids appear to initially stimulate and then block autonomic ganglia. At high doses, neuromuscular blockade results in death of the animal. A wide variety of animals including cattle, sheep, goats, elk, horses, pigs, poultry, and rabbits have been poisoned by Conium maculatum.5-8
Risk Assessment Conium maculatum is unlikely to be a problem to household pets, and no poisoning to date has been reported in the dogs or cats. However, Conium is an invasive noxious weed and increasingly finds its way into the environment of property owners with pets. In some instances, it has even been grown as a garden plant.
