Betty, Leeches are small worms closeley related to earthworms. They generally live in water and attach themselves to mammals and attach themselves and drink their blood. Medicinal leeches are still used in some places. Years ago they were used to "bleed" people. This was to help cure certain diseases according to that which was believed. Doctors also cut patients and bled them. It is believed that George Washington died as a result of being bled too many times while he was ill. Leeches in this day and time are still used to draw blood from areas that would otherwise cause bad bruises such as black eyes. I saw medicinal leeches for sale in a pharmacy in Munich, Germany. Leech and leach are entirely two different and distinct things. Leaching refers to a liquid such as water washing the minerals out of substances. An exact example of this is: Many farms still use manure for fertilizer. It is piled near the farming area until used. If it stays in a pile wthout being used for too long a period of time, rain will wash the mineral content from the manure and its effectiveness as a fertilizer is diminished. If ashes are leached in this manner, potash is washed out. Mixed with water, the potash will produce a weak solution of potassium hydroxide, or potash lye. The stronger form of lye is sodium hydroxide. This is not produced in this manner. This material may seem obnoxious but it is used to process certain foods but not to eat as you would salt.