I know many people who are quacksalvers. They claim to have all this knowledge and try to convince you that you have all these ailments and should therefore do this that or the other.
Have you worked out the meaning yet? A quacksalver is someone who falsely pretends to have a knowledge of medicine.
"medical charlatan," 1630s, short for quacksalver (1570s), from Du. kwaksalver, lit. "hawker of salve," from M.Du. quacken "to brag, boast," lit. "to croak" (see quack (v.)) + zalf "salve." Cf. Ger. Quacksalber, Dan. kvaksalver, Swed. kvacksalvare.