The horticultural trade will use the information to design alabelling scheme for commercially grown plants to inform consumers of potential hazards.
More than 5,000 people a year become ill through contact with plants. Successful treatment is often delayed because doctors are unaware of what was responsible, or the antidotes available. The NPU estimates that one or two people die each year from plantpoisoning.
Last week biochemistry lecturer Paul Napier was jailed for attempting to murder his wife by spiking her gin and tonic with atropine, a derivative of deadly nightshade. Atropine causes dizziness and walking difficulties. It has often been considered a perfect murder weapon because it is quickly expelled from the body, leaving practically no trace.
Poisonous plants can cause symptoms including rashes, blisters, stomach pains and vomiting. Although just 2 per cent of the 150,000 poisoning cases handled each year by the NPU are caused by plants, concern about the health risks has grown in recent years as a wider range has become available in garden centres and nurseries. Children under five are most at risk because they may find berries and leaves attractive to eat.
Some of the most poisonous plants are Taxus baccata, better known as the yew, often found in churchyards; Lathyrus odoratus (sweet pea) and Dieffenbachia or dumb cane, a houseplant.
Ruta graveolens (rue) and Primula obconica (poison primula), which are houseplants, and species of Euphorbia, or spurges, can cause skin reactions including inflammation, itching and bleeding. Poisoning through skin contact is rarely fatal, however.