Starch is an important nutrient in ruminants as an energy source. Utilizing organic acids to reduce starch bioavailability offers a safer approach to sustainable ruminant health and productivity. However, the inconsistent results obtained from published studies necessitate integration through meta-analysis to determine the actual effects. This study aimed to evaluate the effect of reducing starch bioavailability using organic acids on rumen fermentation and ruminant performance by meta-analysis. Hedges’ meta-analysis was conducted by using a random effect. A total of 14 articles were selected from the Scopus platform, with 23 comparative studies. This meta-analysis revealed that starch modification using organic acids influenced rumen fermentation. In vitro studies demonstrated a significant increase (p<0.01) in rumen pH and a reduction in ammonia (NH3) and total volatile fatty acids (VFA) levels (p<0.01). Partial VFA components, including butyrate, iso-butyrate, valerate, and iso-valerate, also showed significant decreases (p<0.01). Total protozoa also obtained a significant decrease (p<0.001). Moreover, in vivo trials indicated ruminant performance with increased milk fat content (p<0.05). In conclusion, the intervention of organic acids for reducing the bioavailability starch in rumen is effectively optimizes rumen health by maintaining fermented products within the normal range and increasing ruminant productivity.