Since their discovery, polyhydroxylated indolizidines have been the focus of attention for both biologists and synthetic chemists. They are classified as iminosugar alkaloids: nitrogen-based carbohydrate mimetics that are potent inhibitors of glycosidases. Many discovered glycosidase inhibitors were found to possess biological activity, and they are therefore considered to be potential therapeutics in the treatment of various diseases such as viral infections, diabetes, or cancer. Not surprisingly, the interest in the preparation of these substances has been enormous. This review presents the latest developments in the synthesis of naturally occurring polyhydroxylated indolizidines and their synthetic enantiomers. In addition, the synthesis of several novel polyhydroxylated indolizidines, which were discovered to have inhibitory activity, is reported. © 2022 Wiley-VCH GmbH.