Medieval Spanish law required a Christian doctor to supervise any Jewish medical care

Evidence

Another law, promulgated in 1397 by Queen Maria of Aragón, forbade Christians from seeking treatment from Jewish doctors and openly expressed the fear of religiously motivated medical murder: Since the perfidious Jews are thirsty for Christian blood, as enemies would be, and it is dangerous for Christians to obtain any medical help from Jewish doctors when they are sick … we ordain and establish that no Jew, in any case of a Christian’s infirmity, should dare to exercise his office unless a Christian doctor will take part in the cure. — James Renton, Ben Gidley (eds.), Antisemitism and Islamophobia in Europe, 365