In this study, the alteration of Jook was studied by analyzing and comparing ingredients of Jook appeared in the reference of cookbooks from 1611 to 1958. 121 kinds of Jooks were mentioned 371 times. The Jooks made only with grains, mostly Hin Jook (white Gruel) made of rice, were recorded 31 times in 10 kinds. Rice or processed rice appeared most (194 times) as main ingredients in Jooks other than Hin Jook. As for condiments, honey and sugar were mentioned 37 times, accounting for one third of the condiments recorded as used for Jooks. The basic ingredient of Jooks were rice, but mostly the Jooks were named after the subsidiary materials. Chinese medicinal ingredients were most among the subsidiary materials; 35 kinds of them were mentioned 73 times. As regards the ingredients of the Jook, the other ingredients were added to the grain ingredients between the 17th century and the 19th century whereas only grains were put into Jook during the 20th century.