This clinical study combined alanyl-glutamine and omega-3 polyunsaturated fatty acids (ω-3 PUFAs) to investigate the effects of parenteral nutrition on postoperative inflammation and nutritional status in patients with gastroduodenal perforation to provide a basis and support for the use of clinical immunonutrients. Patients with gastroduodenal perforations who underwent surgery between January 2018 and December 2023 were included. From the first to the seventh postoperative day, Group A (GA) received conventional postoperative nutrition with fat emulsion (20%), amino acids (17), and glucose (11%) injection; Group B (GB), building on GA's regimen, was additionally treated with 10 g/day of ω-3 PUFAs; and Group C (GC), expanding on GB's regimen, was additionally treated with 10 g/day of alanyl-glutamine. A total of 168 patients were included in the study, with 71 in GA, 30 in GB, and 67 in GC. Total protein and albumin (Alb) levels increased in all 3 groups, with GC showing a more significant increase compared to GB and GA (TP: 7.73 ± 5.00 vs 4.35 ± 5.85 vs 3.92 ± 5.07, P < .05; Alb: 4.07 ± 4.52 vs 1.79 ± 4.00 vs 2.11 ± 4.10, P < .05); C-reactive protein levels decreased in all 3 groups, with the most pronounced decrease in GC (93.71 ± 80.97 vs 72.04 ± 80.48 vs 55.79 ± 83.68, P < .05); the length of hospitalization and among the 3 groups was statistically significant (10.7 ± 2.27 vs 13.39 ± 4.66 vs 12.52 ± 3.46, P < .05), and GB was shorter than GA; the incidence of postoperative complications was significantly lower in GC than in other groups (P < .05). Parenteral nutrition supplemented with alanyl-glutamine and ω-3 PUFAs can increase postoperative total protein and Alb levels, thereby improving patient nutritional status, reducing the production of the inflammatory marker C-reactive protein, mitigating the inflammatory response, and decreasing the incidence of postoperative complications, thus improving patient prognosis.