The newest developments in propolis pharmacological research are summarized. The problem regarding biological studies, caused by the chemical variability of propolis, is discussed. The most important trends and developments in recent propolis research are outlined: biological studies performed with chemically characterized samples, bioassay-guided studies of active principles and comparative biological studies of propolis of different origin and chemical composition. These types of studies are extremely valuable with respect to propolis standardization and practical applications in therapy. They will allow scientists to connect a particular chemical propolis type to a specific type of biological activity and formulate recommendations for practitioners.