Insamsokmieum (人蔘粟米飮), which is a kind of water gruels made with millet, ginseng, glutinous rice, and some minor ingredients, was frequently used as a medicinal food for the royal family, and it appeared first at the 10th year of King Sukjong’s reign. We investigated Insamsokmieum through a literature review and the「SeungjeongwonIlgi(承政院日記)」 of King Sukjong (肅宗) from his 1st year (1674) to 46th year (1720). We analyzed the nutritional value and efficacy of Insamsokmieum. In Oriental medicine, Insamsokmieum is prescribed mainly to treat symptoms such as nausea, languidness, and exhaustion in King Sukjong and Queen Inhyun (仁顯王后). In nutritional terms, Insamsokmieum has higher nutrition density than that of rice porridges (白粥) and has relatively high vitamin and mineral contents. Some nutrients such as leucine and glutamic acid, which are contained in the millet, are also known to help alleviate these symptoms. Whereas there have been studies on the efficacy and types of diet during the Joseon Dynasty, studies regarding nutrition characteristics are lacking. This study will demonstrate the superiority of dietary treatments of the Joseon Dynasty and their potential for application to modern nutrition.