Question

The leeches are used to remove bad blood from human body which
method

Answer 1

Medicinal leeches have three jaws with tiny rows of teeth. They pierce a person’s skin with their teeth and insert anticoagulants through their saliva. The leeches are then allowed to extract blood, for 20 to 45 minutes at a time, from the person undergoing treatment. This equates to a relatively small amount of blood, up to 15 milliliters per leech. Medicinal leeches most often come from Hungary or Sweden.

After the use they were killed by spraying salt on them.