The monoaldehyde form of the ligstroside aglycone is directly formed after the enzymatic deglycosylation of ligstroside after olive fruit crushing in an olive mill. Ligstroside and ligstroside aglycone have similar structure to oleuropein and oleuropein aglycone with the only difference the hydroxy phenolic group in its structure. The concentration of the monoaldehyde form of ligstroside aglycone differs in different olive oils but in general is similar to oleuropein’s aglycone and lower than oleocanthal’s and oleacein’s. The biological activities of ligstroside aglycone are  presented through the studies that have been conducted below.