BACKGROUND: Lung cancer (LC) is one of the leading causes of death worldwide. Treatment methodologies such as chemotherapy and radiotherapy have improved patient survival rates. Nevertheless, these treatments can also lead to adverse reactions and impact patients’ nutritional status and quality of life (QOL). Antibiotics are commonly used for treating infections, but there is still controversy regarding their potential adverse effects on LC patients. OBJECTIVE: This work aimed to investigate the impact of antibiotic adoption on the nutritional status and QOL of LC patients undergoing radiotherapy or chemotherapy, providing valuable insights for the clinical management of LC. METHODS: A meta-analysis approach was employed to comprehensively evaluate the relationship by synthesizing relevant literature. Published studies were identified through searches in databases such as PubMed, EMBASE, Cochrane Library, Web of Science, and CNKI. The inclusion criteria encompassed randomized controlled trials, cohort studies, and cross-sectional studies. Assessment indicators included patient weight, BMI, hemoglobin levels, and QOL. Meta-analysis was conducted using software such as the Cochrane Collaboration and RevMan5.3. Heterogeneity was evaluated using the Higgins I2 index, where values between 25% and 50% indicate moderate heterogeneity, and values greater than 50% indicate substantial heterogeneity. RESULTS: 12 eligible studies involving 1,917 patients were finally included. LC patients who received antibiotics during radiotherapy or chemotherapy were found to have a higher risk of malnutrition. The antibiotic group exhibited a more significant decrease in body mass index (BMI) (P< 0.05) and lower serum albumin levels (P< 0.05) versus the control (C) group. Additionally, the overall QOL scores in the antibiotic group were dramatically lower than those in the C group, showing a significant difference with P< 0.05. Sensitivity analysis indicated that the overall conclusions of this work were robust and unbiased. CONCLUSION: Antibiotics in LC patients undergoing radiotherapy or chemotherapy may increase the risk of malnutrition and decrease their QOL. Hence, physicians should carefully consider antibiotics and take necessary preventive measures and supportive treatments to improve LC patients’ nutritional status and QOL.