We are commenting herein on the published case-control study by Tueme de la Peña et al., “Indocyanine green fluorescence angiography in colorectal surgery: A retrospective case-control analysis in Mexico”.1 The aim of the article was to identify whether indocyanine green fluorescence angiography (ICGFA) lowers the anastomotic dehiscence rate in colorectal surgery. The authors stated they utilized a case-control study design, but we believe that was not the case, for the following reasons: a) A classic case-control study starts from the effect or outcome of interest and advances toward the cause or exposure, and therefore, the exposure status of the subjects is unknown.2 The way in which the article is written suggests that the authors started from the exposure (ICGFA), with an intervention group and a control group, and advanced toward the outcome (anastomotic dehiscence); b) Quantification of the degree of association is lacking. The odds ratio is the relative measure of association classically utilized and reported in case-control studies, through which the authors would have been able to control possible confounding factors that can be directly related to anastomotic leak, regardless of the surgical technique performed, e.g., preoperative bowel preparation, as described in an observational study on the risk factors for anastomotic leak in intestinal surgery3; and c) there is little information in the article for judging the quality of the control group and whether the control group reflected the distribution of the exposure in the study population from which the cases were taken.2 Importantly, the selection of controls is the most difficult task in conducting this type of study.