In the last decades, glycoconjugates from Lycium barbarum L. fruit (Goji berry) have received a great attention for their potential health-promoting effects. The present review includes a survey of extraction and purification methods of these bioactive molecules (L. barbarum polysaccharides, LBPs), along with a dissertation on the structural characterisation of the carbohydrate component. Furthermore, an overview of in vitro, in vivo and clinical studies concerning the hypoglycaemic and hypolipidaemic effects of isolated LBP fractions, is reported. The evidence suggests that these purified components of the Goji berry may be potentially useful as adjuvants in the treatment of diabetes and its correlated illnesses.