Glycemic control is often difficult to achieve in patients with diabetes, especially in the presence of comorbid diseases or conditions such as steroid-use or liver cirrhosis, or in patients receiving enteral nutrition. Moreover, reactive hypoglycemia due to late dumping syndrome in people having undergone gastrectomy is also a matter of concern. Empirically and theoretically, the typical glycemic profiles associated with these conditions have been determined; however, what actually happens during a 24-h span is still somewhat obscure. In order to verify and provide information about the 24-h glycemic profiles associated with these conditions, 8 patients with the 4 above-mentioned conditions were monitored using a continuous glucose monitoring system (CGMS). For all 8 patients, CGMS provided detailed information regarding the 24-h glycemic profiles. The CGM results showed typical glycemic patterns for each condition, and we were moreover able to observe the effects of various practical treatments. Based on these cases, we conclude that the CGMS is highly useful for determining the glycemic patterns of patients with the aforementioned conditions in a practical setting; and this system may be used to monitor the treatment success of such cases. J. Med. Invest. 62: 1-10, February, 2015