Conium maculatum disturbed ground. It is used as a food plant by the larvae of some Lepidoptera species, including silver-ground carpet. The poison hemlock moth ("Agonopterix alstroemeriana") feeds on the plant during its larval stage. "A. alstroemeriana" has been widely used as a biological control agent for "C. maculatum". Poison hemlock flourishes in the spring, when most other forage is gone. All plant parts are poisonous, but once the plant is dried, the poison is greatly reduced, although not gone completely. The plant is poisonous to animals that graze on it. "Conium" contains the piperidine alkaloids coniine, N-methylconiine, conhydrine, pseudoconhydrine and gamma-coniceine
Poison drilling rigs). Plant-based contact irritants, such as that possessed by poison ivy or poison oak, are often classed as allergens rather than poisons; the effect of an allergen being not a poison as such, but to turn the body's natural defenses against itself. Poison can also enter the body through the teeth (in the controversial case of dental malpractice), faulty medical implants, or by injection (which is the basis of lethal injection in the context of capital punishment). In 2013, 3.3 million cases of unintentional human poisonings occurred. This resulted in 98,000 deaths worldwide, down from 120,000 deaths in 1990.