Crocus or autumn crocus is one of the most dangerous plants in the world. Crocus contains colchicine, a deadly toxin to humans, from which there is no antidote. Colchicine poisoning is fraught with critical decrease in blood pressure and, as a consequence, cardiac arrest.
Lilies of the valley are quite beautiful flowers that are often sold as whole bouquets. But they are not as harmless as they seem. Glycosides contained in this poisonous plants, are dangerous for people with heart disease, as it causes arrhythmia and break the heart. Poisoning is accompanied by nausea, vomiting, diarrhea and even seizures.
Oleander is widely used in landscape design in the regions with a subtropical climate, in particular the Black Sea coast of the Caucasus. it is necessary to be very careful dealing with them - a complex of toxic substances affects the nervous, digestive and cardiovascular system at the same time. A death is quite likely in case of prolonged contact with oleander.
The latex (sap) of this plant can cause lung failure and cardiac arrest. A powerful opiate - heroin is extracted from the poppy. Not only the drug is deadly dangerous, but the drug cartels as well, leading incessant war with each other for control of the poppy fields.
Poinsettia is not as dangerous as other plants on this list, but it still can seriously harm you. Especially if you want to consume it. The milky sap causes severe poisoning, accompanied by vomiting and diarrhea. Keep it out of the reach of children and pets.