Hematophagous species including leeches have a certain type of active compound in their body secretions. Leeches have been used in ancient medicine for centuries. Indians, Egyptians and the Greeks have used this in their medical treatment of patients with many ranges of diseases including skin diseases, hair treatment, urinary and reproductive system problems, inflammation and others. In the beginning, the leech was used to remove excess blood from patients as many diseases were related to excess blood. Later the saliva of a leech was found to consist of a very biologically active compound including peptides and proteins that is important in the treatment of a lot of sicknesses. Today leech is being used in modern medicine for cardiovascular diseases, cancer, metastasis and other infectious diseases.

In Asia, including Indonesia and Malaysia, (leech oil) is being extracted from leeches and used for many types of traditional remedies. Some of the use of this oil is still being questioned but people are still inclined to use it as per the many claims raised by its users. Many people still do not know the extent of the benefits of the leech. It is good to see that more research is being carried out by hospitals and medical schools to research this species so it may help modern medicine and civilization. Today leech can be freely found in heavily dense areas where anyone can catch it by hand and it is still in abundance. One day this species may also become extinct if its habitat is not taken care.

Many locals especially those who produce minyak belacak (leech oil) only think about the profit they make from selling the oils. They are not aware how their everyday work could one day change modern medicine and how we treat diseases in the world.