Nephrolithiasis, or kidney stone disease, remains a significant global health issue with high recurrence rates despite the availability of advanced treatment modalities. This quasi-experimental study explores the therapeutic potential of banana stem juice (Musa paradisiaca L.) as a safe and cost-effective adjunct in the conservative management of renal calculi. A total of 60 adult participants diagnosed with nephrolithiasis were recruited and divided equally into experimental and control groups. The experimental group received 100 ml of freshly prepared banana stem juice twice daily for six weeks along with standard medical advice, while the control group received standard care alone. Baseline and post-intervention assessments included ultrasonographic measurement of stone size and structured evaluation of participants� knowledge regarding nephrolithiasis prevention and management. Post-intervention analysis revealed a statistically significant reduction in mean stone size in the experimental group, decreasing from 6.73 ± 1.31 to 0.67 ± 0.88 mm (p < 0.001), compared to a more modest reduction in the control group from 5.67 ± 1.85 to 2.93 ± 2.39 mm. Knowledge scores improved in both groups; however, between-group difference was not statistically significant. No adverse effects were reported among participants consuming the banana stem juice, indicating its safety and tolerability. These findings suggest that banana stem juice can effectively contribute to kidney stone size reduction and support overall patient well-being when used alongside conventional therapy. It also underscores the potential role of traditional dietary remedies in modern nephrolithiasis management, warranting further clinical validation through larger randomized trials. © 2025 Elsevier B.V., All rights reserved.