The aim of this study is to determine the effect of the interactive nurse support program developed as a mobile application on patient outcomes (symptom management, quality of life, perception of social support and anxiety) in colorectal cancer patients receiving chemotherapy during the COVID-19 process; It was planned in a randomized controlled, single-blind design. In the study, a mobile application will be designed for colorectal cancer patients with the content created in line with the literature. In the application, the about COVID-19 module, which includes information for colorectal cancer patients during the COVID-19 process, the learning module in which the symptoms and suggestions for colorectal cancer patients receiving chemotherapy are included, the discussion module where patients can share their knowledge and experiences with each other, The ask the expert module, where nurses and physicians can ask questions, will be comprised of the lived stories module and the communication sections, which include interview videos made with individuals who are in remission only after completing the treatment related to the disease. A pretest consisting of Personal Information Form, Multidimensional Perceived Social Support Scale EORTC QLQ-C30 and CR29 Quality of Life Scale, ECOG Performance Scale and Beck Anxiety Scale will be administered to all patients included in the study. The mobile application will be installed on the phones of the patients in the experimental group and they will be used for 12 weeks. Patients in the control group will receive standard care during this process and no intervention will be made. In the sixth and twelve weeks, all participants will be given a posttest. The change in symptom management, quality of life, perceived social support and anxiety levels of the experimental group after mobile application use will be evaluated.