Is propolis safe as an alternative medicine?

Propolis is a resinous substance produced by honeybees as defense against intruders. It has relevant therapeutic properties that have been used since ancient times. Nowadays, propolis is of increasing importance as a therapeutic, alone or included in many medicines and homeopathic products or in cosmetics. Propolis is produced worldwide and honeybees use the flora surrounding their beehives for its production. Therefore its chemical composition may change according to the flora. The phenolic and volatile fractions of propolis have been revised in the present study, as well as some of the biological properties attributed to this natural product. An alert is given about the need to standardize this product, with quality control. This has already been initiated by some authors, mainly in the propolis from the poplar-type. Only this product can constitute a good complementary and alternative medicine under internationally acceptable quality control.