Heating or ginger extract reduces the content of Pinellia ternata lectin in the raphides of Pinellia tuber.

Pinellia tuber, the dried tuber of Pinellia ternata, causes a very strong acridity sensation in the oral and laryngopharynx mucosa when taken orally in its unprocessed form. In traditional Chinese medicine (TCM), this sensation has been called "toxicity", and Pinellia tuber must be processed using ginger extract, licorice, or alum. In Japanese traditional Kampo medicine, since "toxicity" can be eliminated by decocting, it should not be processed.

Historical Study for the Differences of Processing of Tuber Between China and Japan.

Pinellia Tuber (the dried tuber of (Thunb.) Makino [Araceae]) (PT) is a crude drug used in traditional Chinese medicine (TCM) and Japanese Kampo medicine. PT is subjected to additional processing before use in TCM because of its toxic, while the processing has not been used in Kampo medicine.

The acrid raphides in tuberous root of Pinellia ternata have lipophilic character and are specifically denatured by ginger extract.

Unprocessed dried tuberous root of Pinellia ternata (Pinellia Tuber) has been used as a component of traditional Japanese Kampo medicine, while this crude drug is usually used after processing with Ginger in traditional Chinese medicine (TCM). It is known that the raphides contained in unprocessed Pinellia Tuber can induce severe acrid irritation of the oral and laryngopharynx mucosa when it is boiled insufficiently. However, the mechanism of the inducing irritation by the raphides nor that of the detoxification by heat or processing with Ginger have been left unclear, mainly because of the difficulties in the extraction and the purification of the raphides and in the assays of acridity.