The Collaborative International Dictionary
Diacatholicon
Diacatholicon \Di`a*ca*thol"i*con\, n. [Pref. dia- + catholicon.] (Med.) A universal remedy; -- a name formerly given to a purgative electuary.
Wiktionary
diacatholicon
n. (context medicine dated English) A universal remedy; a certain purgative electuary.