An oral delivery system (ODS) is disclosed, the oral delivery system (ODS) comprising a first compartment (FCO) and a second compartment (SCO), said first compartment (FCO) comprising a first component (FC) comprising natural unbranched polysaccharide, said second compartment (SCO) comprising a second component (SC) comprising multivalent cations, wherein the oral delivery system (ODS) is adapted for administering the first and second components (FC, SC) in a synchronized manner to the oral cavity, whereby a bioadhesive gel is formed from said natural unbranched polysaccharide and said multivalent cationsin a cross-linking reaction.