- For other uses, see Horseradish (disambiguation).
Horseradish is a bitter root that is a cure to Medusoid Mycelium.
Beatrice Baudelaire created a hybrid between horseradish and an apple tree, resulting in bitter apples. Unfortunately, the hybrid damages fetuses. Because Beatrice was pregnant with Violet, she could not eat the hybrid. Neither could Kit Snicket when she was infected with the Medusoid Mycelium and also pregnant with her baby.
Ishmael enjoyed apples from the hybrid. Because he has been eating them for so long, he is immune to the Medusoid Mycelium.
- The compound in the hybrid (and horseradish itself) that could have caused concern for Beatrice and Kit while pregnant was likely Allyl isothiocyanate (mustard oil). In high quantities, such as is found in supplements that are used medicinally, it can irritate the mucous membranes and cause heartburn. There is conflicting anecdotal evidence as to whether or not horseradish should or shouldn't be consumed during pregnancy. There isn't any scientific evidence that mustard oil, when consumed in amounts found in horseradish naturally, poses any danger to the fetus.
- In The Austere Academy (part one) Isadora Quagmire mentions the apples taste like horseradish. This may be a reference to the horseradish apples in The End.