Related על פסחים 2:6

Rabbi Yehuda ben Beteira says, they fulfill [the obligation of eating bitter herbs] with lettuce (חזרת) and with mustard. Rabbi Yishmael bar Rabbi Yochanan ben Berokah says, one does not fulfull [the obligation] with anything that burns [the mouth]. Rabbi Yehuda says, anything that makes one pale [after eating it] fulfills [the obligation]. They may fulfill [the obligation] either with wet or dry [bitter herbs]. Rabbi Meir says, [the halacha should rather be formulated as] "they even fulfill [their obligation] with dry [bitter herbs]." Rabbi Tzadok says, [the halacha should rather be formulated as] "they even fulfill [their obligation] with pickled [bitter herbs]."