Pharmacology of lemongrass (Cymbopogon citratus Stapf). III. Assessment of eventual toxic, hypnotic and anxiolytic effects on humans.

A herbal tea (called an abafado in Brazil) prepared from the dried leaves of lemongrass was administered to healthy volunteers. Following a single dose or 2 weeks of daily oral administration, the abafado produced no changes in serum glucose, urea, creatinine, cholesterol, triglycerides, lipids, total bilirubin, indirect bilirubin, GOT, GPT, alkaline phosphatase, total protein, albumin, LDH and CPK. Urine analysis (proteins, glucose, ketones, bilirubins, occult blood and urobilinogen) as well as EEG and EKG showed no abnormalities. There were slight elevations of direct bilirubin and of amylase in some of the volunteers, but without any clinical manifestation. These results taken together indicate that lemongrass as used in Brazilian folk medicine is not toxic for humans. The eventual hypnotic effect of lemongrass was investigated in 50 volunteers who ingested samples of lemongrass and a placebo under double-blind conditions. The parameters (i.e. sleep induction, sleep quality, dream recall and rewakening) did not show any effect of lemongrass as compared to the placebo. Eighteen subjects with high scores of trait-anxiety were submitted to an anxiety-inducing test following taking lemongrass or placebo under double-blind conditions. Their anxiety levels were similar, indicating that the abafado of the plant does not have anxiolytic properties. It is concluded that lemongrass, one of the most popular Brazilian herbal medicines, used for its alleged CNS-depressant effects, is atoxic but lacks hypnotic or anxiolytic properties.