“lead has NO medicinal quality it is poison.”
So is arsenic, which was used to treat syphillis, successfully, for many years. Chemotherapy is the use of poisons to kill cancer in such doses that it kills the cancer faster than it kills the person who has cancer. Antibiotics are also poisons. Just because it is poison doesn’t mean it cannot have medical uses.
Just because it has medical uses doesn’t necessarily recommend it for them, either. You must do a cost/benefits analysis and see if it is worth using. If lead and lead salts are all you have, it might well be worth using.
Lead and tin compounds have anti-fungal and anti-bacterial effects.
http://www.springerlink.com/content/n55772025q382801/