Poisonous plants are those which contain substances harmful to the body to the point where its ingestion, in some cases can cause death. Among the toxic substances that have these plants are oxalates, alkaloids, saponins and resinoid, plus some harmful minerals absorbed from soil as nitrate or selenium. Toxic plants are distributed worldwide. These include the hellebore, which grows in swamps and whose rhizomes contain a toxic substance called eleborina, the cherry laurel, native to Asia, which has in its leaves a powerful poison: prussic acid, nux vomica, which grows in India, Australia and Sri Lanka, whose seeds contain strychnine, a deadly poison in small doses, the hemlock, which is found in moist, shady places, and contains cicutina or conicina, besides the rude, the autumn crocus, some bittersweet, wisteria glycine or the herb St. Kitts and celandine. Certain ornamental plants are poisonous: the case of mistletoe, laurel white, pink or red, and the datura, among others.
These plants can cause diverse effects such as skin irritation (stinging nettle), hallucinations (jimsonweed), paralysis of respiratory muscles (nux vomica), heart failure (yew), paralysis progressing to respiratory paralysis ( hemlock).
The main assets of some poisonous plants are used in alternative medicine to cure various diseases. This is the case of the autumn crocus (indicated for gout and rheumatism), the bittersweet (effective for colds and rheumatism lung) and datura (optimal sedative).