Here are some of the more common herbs to be wary of, including a couple that can “worke eternal sleepe.” If you choose to grow these herbs, be sure to carefully label each herb and plant them away from culinary herbs and edible crops. Avoid planting them if you have pets or young children that may be tempted to nibble them.
Aconite (Aconitum spp.): This herb, also known as monkshood and wolfsbane, deserves a skull-and-crossbones; it’s highly poisonous.
Comfrey (Symphytum officinale): Don't take internally. Laboratory research indicates that comfrey, even in low concentrations, is carcinogenic in rats.
Deadly nightshade (Atropa belladonna): In folklore, this one is a favorite ingredient of witches’ brews. The common name says it all.
Foxglove (Digitalis purpurea): The source of a powerful heart medication, foxglove can cause convulsions and even death if used improperly.
Hellebore: Both American false hellebore (Veratrum viride) and black hellebore (Helleborus niger) are dangerous characters; they are major-league skin irritants and can be fatal if ingested.
Hemlock (Contium maculatum): Also known as poison hemlock. Think nausea, paralysis, and death.
Pokeweed (Phytolacca spp.): All parts of mature plants, including their pretty purple berries, are toxic.