Latex samples of Euphorbia tanquahuete Sesse et Moc. (Euphorbiaceae), collected in the four moon phases, were analyzed to determine the composition of the secondary metabolites and to identify the main components. In the four samples studied only terpenes and steroids were found. The concentration of these compounds varies according to the collection time (moon phase). The major components of the acetonic extracts are lupeol and b-sitosterol
