Introduction: Chemical, ethnopharmacological and pharmacological research on Lippia alba (Mill.) N.E. Brown and the evidence that exists for its various usages have been looked for, focusing on high quality studies.
Ethnopharmacological investigation: The species is mainly used against digestive and respiratory ailments, and as a sedative and antihypertensive remedy.
Chemical constituents: Seven chemotypes exist for the essential oil, the non-volatile compounds are iridioids, phenylethanoids, flavone glycosides and biflavonoids.
Biological activities and ethnopharmacological appraisal: Some positive, although partial, results have been obtained on sedative and anxiolytic activities. Real effects in other traditional uses can mainly be explained by anti-infectious and analgesic properties, at the moment.
Conclusion: Well conducted biological studies are still needed for several indications of this species. Its use as a sedative deserves a clinical investigation. The chemical variability of the species seems important both in the essential oil and in non-volatile compounds, so future research on the pharmacological properties of these extracts should provide more chemical data which will increase their validity.