Leeches are friends of doctors.
Recently, hirudotherapy has become very popular - treatment with leeches.
They treat cardiovascular, urological, gynecological diseases.
In many cases, leeches are an alternative to surgery.
By the way, if you find leeches in the swamp, then you should not fit them to your body, these are not the leeches from which you will get a good result. In medicine, not those leeches that swim in the swamp, but those that are grown in biofactories are used.
I used to think that leeches suck out bad blood, this is how people are treated. But the main value is her drool, which she injects into the patient's body immediately after the bite.
I've just upvoted @yakubenko's content.