An integrated approach to the pharmacological evaluation of traditional materia medica. A triple-tiered working model is projected for the pharmacological evaluation of crude drugs prescribed in traditional medical practices. Of the proposed component tests and procedures, the majority have had their usefulness already validated in natural product pharmacological research. First-level investigations (herbalist consultations/professional attestations, hippocratic screening and literature surveys) provide first-hand pharmacological information about traditional materia medica. Second-level investigation comprising bioassay-modelled tests (brine shrimp toxicity test, opiate receptor-binding studies, fertilized sea urchin egg test, platelet adenyl cyclase/phosphodiesterase assays, hexobarbital-induced sleeping time test, antimicrobial assays, isolated guinea pig ileum test and pharmacodynamic screening) are designed to extend the mode(s) of drug action suggested by the first-level procedures. Based on data from Level 1 and Level 2 findings, third-level experiments are specific tests tailored to confirm the pharmacodynamic/kinetic properties and clinical efficacy of traditional drugs. Level 2 and Level 3 tests may be combined in monitoring fractionations and subsequent isolation of unique crude drug constituents with potential application in conventional therapeutics.