Acute poisoning through consumption of plants picked from the wild is not uncommon in Hong Kong. Gelsemium elegans Benth. is one of the most poisonous native plants which can cause toxicities ranging from dizziness to respiratory depression and muscle paralysis after ingestion. We report three cases of gelsemium poisoning in a family after consumption of a homemade herbal soup made of a plant believed to be Cassytha filiformis Linn. collected in the countryside. All of them presented with dizziness, nausea and generalised weakness and bilateral ptosis about 1 hour post-ingestion. C. filiformis is generally regarded as non-toxic and it does not contain gelsemium alkaloids. The exact origin of the gelsemium was not known in this case. This case highlighted the potential public health threat posed by the practice of picking and consumption of wild plants. Emergency physicians should also be aware that the plant species reported by the patients may not always be the ones causing clinical toxicities. (Hong Kong j.emerg.med. 2015;22:60-63)