Poison plant handbook uncovers touch-me-nots

Local | Riley Chan Apr 17, 2018
The Hospital Authority (HA) has issued an online illustrated handbook about poisonous plants in a bid to prevent people from inadvertently poisoning themselves.

The digital version of the Atlas of Poisonous Plants in Hong Kong - A Clinical Toxicology Perspective, which lists 117 types of poisonous plants found in Hong Kong, was first released in 2016.

The HA reported 30 cases of plant poisoning in the past decade, a third of which involved the use of Gelsemium elegans, commonly known as heartbreak grass and one of the four most poisonous plants in Hong Kong.

Ingestion of the plant could result in respiratory depression, depression of the central nervous system or even death, according to Tony Mak Wing-lai, chief of service of the department of pathology at Princess Margaret Hospital.

He said in 2007, a woman was severely poisoned and required intubation after ingesting Gelsemium elegans collected in Lantau Island, which she mistook for the non-poisonous Mussaenda pubescens, a plant from the coffee family.

In 2008, a family was poisoned after eating a commonly used food - roots of "hairy fig" Ficus hirta - which were contaminated with roots of Gelsemium elegans.

Mak said a lot of poisonous plants are hard to identify. One common example is Amanita farinosa, a poisonous mushroom. Eating it could lead to liver failure or even death. People often also confuse the Rhododendron simsii, a rhododendron species, with the Bunga Raya, commonly known as the hibiscus. The former is colorful but poisonous, while the latter is said to have medicinal powers.

In 2008, a 57-day old infant exhibited symptoms of vomiting, muscle twitching, cyanosis and loss of consciousness after being fed formula milk prepared with a decoction of the "red flower" for airway problems.

He required intubation and mechanical ventilation. His condition later improved and he was discharged eight days after being admitted. The "red flower" was later found to be Rhododendron simsii.

Mak warned people not to eat unidentified plants, to avoid being poisoned.

The HA Toxicology Reference Laboratory spent five years from 2011 to 2016 to prepare the publication, which lists the toxic constituents, poisoning features, clinical treatment and cases of 117 plants.

The online version is available to the public for free.

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March 2019