Lemongrass Lemongrass is a strong, sweet, lemony fragranced essential oil extracted from the grasses Cymbopogon citratus or flexousus. The oil has a marked revitalising action especially useful during recovery after an illness. It is also helpful for the digestive system encouraging appetite and muscular action, so is good for colitis and indigestion. Lemongrass is a strong antiseptic and good for alleviating fever and headaches. It is also useful in repelling insects.