Poisonous plants
by Dr John Winsor - The Sunday Times of Malta


Many trees and plants are poisonous, and a hazard for inquisitive youngsters who are always putting things in their mouths. Naturally-occurring poisons are concentrated in seeds and berries but leaves, flowers, sap and roots can contain a considerable amount. As a general rule, unripe fruits are more dangerous than ripe ones.

The first thing a doctor will need to know is what and how much of the poisonous plant was eaten, when it was eaten, and what part of the plant was consumed. They will also need to know how old the patient is and whether they have already vomited after eating the plant. If possible, save what remains of the plant that was eaten and let the doctor or hospital see it for identification purposes as there are specific antidotes to certain plant poisons.

Garden plants that cause problems include laurel leaves and their black-currant-looking berries, both of which contain derivatives of cyanide. Lily of the Valley flowers and berries contain a chemical which affects the rhythm of the heart, but fortunately the poison is poorly absorbed so its effects are rarely seen.

Other common culprits include Laburnum — whether in the form of seeds or bright yellow flowers — which contains a chemical that poisons in the same way as nicotine; wisteria pods, which bring on gastroenteritis, and lupin pods, which cause vomiting and convulsions. Aconite (monkshood) is the most poisonous plant in Europe and it can kill. Few people realise that rhododendron seeds produce urinary and gastroenteritis symptoms, such as pain when passing water, diarrhoea and vomiting.

Poppies contain over 100 different kinds of addictive drugs, the most powerful being the basic derivatives of morphine and codeine. As it is now well known, the pretty blue flowers of morning glory conceal the drug LSD, which produces horrific hallucinations.

Away from the garden and into the countryside, yew seeds are dangerous — even lethal if chewed, while holly berries act as a purgative. Deadly nightshade isn’t as bad as its name suggests — at least 10 or 12 berries are needed to produce diarrhoea, headaches and abdominal pain but still should not be eaten. The fox-glove — famous for giving us the drug digitalis for heart failure and slowing the heart rate — is not good for healthy hearts. Even the benign sounding buttercup should be avoided, as it belongs to the same family as monkshood and can cause blistering of the mouth, colic and diarrhoea.

Funghi such as wild mushrooms and toadstools are not often toxic if they are cooked as the poisons are broken down by heat, but problems can arise if they are eaten raw. But the best protection against plant poisoning is knowing what is dangerous and educating your children.