In plants or insects, pyrazines play the roles of attractants, feromones and signal substances. Similar substances were found in food and therefore their sensoric properties were investigated. Pyrazines are also synthesized by a number of fungi, such as antibiotic aspergillic acid and fungicidal pigment pulcherrimin. Synthetic pyrazines are used as additives in food manufacture and in tobacco industry. Some of them are important pharmaceuticals such as sulfonamides sulfapyrazine and sulfalene, antituberculotic pyrazinamide, potassium-sparing diuretic amiloride, hypolipidemid acipimox, peroral antidiabetic glipizide, benzodiazepine hypnotic eszopiclone, potential antineoplastic pyrazine diazohydroxide and antivirotic 6-fluoro-3-hydroxypyrazine-2-carboxamide.