Wild taro (Colocasia esculenta var. antiquorum) grows naturally in streams and ravines. Its leaves resemble those of edible taro, but the plant is slightly smaller. Ingestion of wild taro can be fatal; survival is possible only by drinking "di jiang" (earth slurry, prepared by mixing soil from three feet underground with water and letting it settle) and fecal juice.
Another prescription: Boil soybeans [Glycine max] to make a thick decoction, and drink it warm multiple times; this is highly effective.
Taro cultivated for three years without harvesting may transform into a toxic variety referred to as "[missing character] taro". Ingestion of this also proves fatal, and the treatment method is the same as described above.