Plantamajoside is a bioactive caffeic acid derivative, a dihydroxyphenethyl glucoside in the group of polyphenolic compounds. It is one of the principal caffeic acid glycoside in the Plantago Digitalis, Hemiphragma, Lagotis, Picrorhiza, Rehmannia, Veronica, Wulfeniopsis and Wulfenia genera within the Plantaginaceae family. This compound is also present in the genera Aeschynanthus and Chirita of the Gesneriaceae family and the genus Boschniakia of the Orobanchaceae family. Plantamajoside is present in the greatest concentrations in roots of young plants, but it is also found in seeds, flower stalks, stems, leaves, in vivo cultivated plant cells and transgenic root cultures. Plantamajoside is used as a biomarker in chemotaxonomical studies, and is a compound with numerous biological applications and considerable pharmacological potential. It is a protective agent against ultra-violet light in plants and acts as antioxidant agent with very low toxicity. In addition, plantamajoside can also be industrially synthesized. This review aims to give an overview of plantamajoside in various plantago species as well as its potential as a biomarker and as a new drug compound.