Objective To investigate the effects of nasojejunal nutrition enhanced by glutamine (Gln) on intestinal mucosal barrier and immune function of old patients with severe traumatic brain injury. Methods A total of 67 old patients with severe traumatic brain injury were randomly divided into 2 groups, i.e. the control group (n=34) that adopted the conventional nasojejunal nutrition and the observation group (n=33) that adopted nasojejunal nutrition with Gln. Venous blood samples of two

groups before and one and two weeks after administrating nasojejunal nutrition were collected. Blood albumin (ALB), prealbumin (PA), hemoglobin (Hb), serum diamine oxidase (DAO), immunoglobulin (IgG, IgM, IgA), and T lymphocyte subgroup level (CD4+/CD8+) were detected and complications of two groups were observed. Results Nutritional status of two groups was significantly improved after administrating nasojejunal nutrition (P<0.05) and the levels of ALB and PA of the observation group two weeks after administrating nasojejunal nutrition were significantly higher than those of the control group (P<0.05). The level of DAO of the observation group was significantly lower than that of the control group (P<0.05) and levels of immunoglobulin (IgG, IgM, IgA) and T lymphocyte subgroup (CD4+/CD8+) were better than the control group (P<0.05). But the difference of complications between two groups was not statistically significant (P>0.05). Conclusion Nasojejunal nutrition enhanced by Gln is helpful for improving the intestinal mucosal barrier and immune function of old patients with severe traumatic brain injury and increasing the therapeutic effect of nutritional support.