BACKGROUND & AIMS: We performed this systematic review and dose-response meta-analysis of randomized clinical trials (RCTs) to determine the effects of oral nutritional supplements (ONS) in cancer patients undergoing chemo (radio) therapy on body weight, body mass index (BMI), serum albumin, fatigue, quality of life (QOL), patient-generated subjective global assessment (PG-SGA) score and C-reactive protein (CRP). METHODS: Appropriate search terms were used for systematic search in PubMed, Scopus, and Web of Science, till April 2024. Both pairwise and dose-response meta-analyses were done. Random effects model was applied for analyses. RESULTS: We found that ONS administration significantly improved weight gain [weighted mean difference (WMD): 1.18 kg
95 % CI, 0.20 to 2.17, P = 0.019
I CONCLUSIONS: In conclusion, ONS can help improve various cancer-related complications
however, further good-quality research is still needed. The study found that ONS significantly improves QoL, reduces fatigue, and promotes body weight gain in cancer patients. However, there were no significant effects on BMI, serum albumin, CRP, or PG-SGA scores.