White yam looks like taro: where does it grow, how toxic is it, and what should you do if you eat it by mistake?

White yam, also known as bangshu, wild kudzu yam, Dali wang and so on, has a flowering period from April to May and a fruiting period from July to September. Its exterior is brown, with scattered fibrous roots, and the cut surface is white when fresh. So, where does this white yam, which looks like taro, grow? Is it highly toxic? What should you do if you eat it by mistake?

1. Where does the white yam, which looks like taro, grow?

White yam is distributed in Fujian, Guangdong, Guangxi, Yunnan, and Chamdo and Bomi in Tibet, China. It grows in thickets by ravine edges or at forest margins below 1500 m in elevation; it may be wild or cultivated.

2. Is white yam highly toxic? What should you do if you eat it by mistake?

The rhizome of white yam contains the toxic components dioscorine and dioscorinine, which belong to tropane alkaloids containing a lactone ring. After poisoning from ingestion, symptoms include burning pain in the mouth, tongue and throat, salivation, nausea, vomiting, abdominal pain and diarrhea; in severe cases, difficulty breathing and cardiac arrest, coma, and even death may occur.

If it is accidentally ingested and poisoning symptoms appear, the person should be promptly sent to a medical institution for induced vomiting, gastric lavage, catharsis and fluid infusion, and for oral administration of substances such as egg white, milk, activated charcoal or a general antidote, along with symptomatic treatment.

Because it is difficult for people to distinguish white yam from edible yam-type plants, and the tubers of white yam are highly toxic, they can be used as medicine only after professional processing, and should be taken under the guidance of a traditional Chinese medicine practitioner. Disease control experts advise people not to pick, process or eat white yam, to raise awareness of prevention and self-protection, and to prevent incidents of white yam poisoning.