Complicated intra-abdominal infection cIAI as a common infectious disease in surgery is characterized by difficult treatment complex and variable condition high prevalence and high mortality rate often combined with gastrointestinal dysfunction reduced intestinal mucosal barrier function intestinal flora imbalance and loss of nutrients which seriously affects the patient 's prognosis. In recent years with the continuous development of diagnosis and treatment technology the survival rate of patients has been improved but there are still more complications and long hospitalization time. In this context nutritional therapy has become an important means of supplementing drug therapy and surgical intervention. As clinical nutrition continues to advance nutritional therapy strategies are being developed and optimized and clinicians are gradually taking the concept of nutritional therapy deeper and deeper into their hearts. Early nutritional support has been shown to improve patients ' nutritional status enhance immunity promote postoperative recovery and reduce complications and mortality. Individualized nutritional protocols are nutritional treatment plans based on patients' individual differences including their conditions nutritional status and tolerance which can more effectively improve patients' nutritional status and therapeutic effects. Overall nutritional support has an important role in the treatment of cIAI but there are still some controversies and challenges such as accurately assessing the nutritional needs of patients choosing the most suitable nutritional therapy and preventing complications of nutritional therapy. In the future with the advancement of research technology and the accumulation of clinical experience the application of nutritional therapy in complex abdominal infections will hopefully make more progress.