Alexander Dyce, A General Glossary to Shakespeare's Works

conger “and fennel—Eats,” 2 HENRY IV., ii. 4. 235. “Conger with fennel was formerly regarded as a provocative” (STEEVENS) . “Fennel was generally considered as an inflammatory herb; and therefore, to eat conger and fennel was to eat two high and hot things together, which was esteemed an act of libertinism.” Nares's Gloss. in “Fennel.” “It [fennel] was used as a sauce with fish hard of digestion, being aromatic, and, as the old writers term it, hot in the third degree.” Beisly's Shakspere's Garden, p. 158.