With the emerging diseases and the economic turmoil in the society, people tend to take herbal plants instead of synthetic drugs. Majority of the Filipinos regularly drink kalamansi juice, in different preparations, for boosting the immune system. This scenario had encouraged the researchers to conduct phytochemical and antimicrobial screening of Kalamansi juice since commercial products have evolved in the market. A commercially prepared Kalamansi fruit extract had evaluated the presence of Alkaloid, Tannins and Saponin while Kirby-Bauer disk diffusion method and Minimum inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) and Potency tests were performed for the antimicrobial evaluation. Likewise, Ames test was utilized for the mutagenic analysis. Results reveal that none of the secondary metobolite is detected. A zone of inhibition of 10.63mm ± 0.6844 is measured against Escherichia coli, while 11.94mm ± 1.1480 of Staphylococcus aureus and 10.25 mm ± 0.4945 for the Pseudomonas aeruginosa. Antimicrobial analysis shows that the fruit extract has a lesser strength to have an antibacterial property. Furthermore, MIC value is identified at 31.25 mg/ml (P. aeruginosa), 15.63 mg/ml for E. coli, and 500 mg/ml towards S. aureus. MBC test reveals that at 31.23 mg.mL concentration can effectively inhibit the growth of P. aeruginosa only. Kalamansi extract has a comparable strength with Azithromycin using E. coli and P. aeruginosa. However, it is not equipotent with Oxacillin in S. aureus. Ames test shows that the extract and/or other ingredients of the product have mutagenic property using Salmonella typhimurium TA98.