Unsu sanitized by Undan has marvelous germicidal power on pathogenic germs as natural antibiotic.

One piece of undan weighing 2.5 grams sterilizes about 2,000 liters of water.

Unsu is not decomposed for three months and has good taste.

When one wants to use it for the treatment of diseases, one should put it into water above 70 degrees centigrade and properly cool the water before drinking.

It is not affected by sediment as it always floats on the water and can be applicable to any drinking water.

It is appreciated as an ideal water disinfectant.