When it detectssmoke, thealarmemitsacompoundcalledallylisothiocyanate, whichis responsible forthepungenttasteandsmellofstinkyfoodslikemustard, horseradishand wasabi.
Eugenol (4-allyl-2-methoxyphenol) is a fragrant compound that is commonly contained in various sorts of plants, especially in spices and medicinal herbs.