Lemongrass is a plant. The leaves and the oil are used to make medicine. Lemongrass is used for treating digestive tract spasms, stomachache, high blood pressure, convulsions, pain, vomiting, cough, achy joints (rheumatism), fever, the common cold, and exhaustion. It is also used to kill germs and as a mild astringent. Some people apply lemongrass and its essential oil directly to the skin for headache, stomachache, abdominal pain, and muscle pain.