Abstract: Low molecular weight sulphated L-fucose polysaccharide fraction having a molecular weight ranging from 11 to 30 kDa when measured with TEST A, a sulphate content ranging from 10 and 50% w/w relative to the total weight of the fraction, a fucosis content ranging from 30 and 70% w/w relative to the total weight of the fraction, and a polydispersity index ranging from 1 and 2, wherein the fraction is obtainable by free radical depolymerisation of a crude fucan of vegetal origin; process for manufacturing same; pharmaceutical composition and medicament containing same and their use for inhibiting neovascularisation.