Maror

Bitter Herbs (usually horseradish) symbolize the bitterness of Egyptian slavery. The maror is often dipped in charoset to reduce its sharpness. Maror is used in the seder because of the commandment (in Numbers 9:11) to eat the paschal lamb "with unleavened bread and bitter herbs." Some prefer mild horseradish at the seder; others say that it doesn't serve its purpose (to remind us of the bitterness of slavery) unless it's hot enough to bring tears to the eyes.

Horseradish is usually kept in the refrigerated foods section. If fresh horseradish root is available, it will be in the produce section.