Native starch granules are semi-crystalline and resist hydrolysis by amylases. When gelatinised, however, they are readily hydrolysed and converted to sugars and dextrins. Factors that control the rate and profile of hydrolysis by amylase in vitro and in vivo are interconnected and make research within this field complicated. This review is an attempt to address some of these issues and direct readers to primary sources of information concerning these features. Each of the different heading within this text could be converted into a review within its own right and hence selection with respect to literary sources has had to be made.