To overcome the burden of antimicrobial resistance, greater attention has been paid to antimicrobial activity screening from natural products. One such natural products used for therapeutic purposes is Alum. Besides, Ayurvedic Bhasma formulations have been used for treatment of various ailments for thousands of years all over the world and widely in India. Hence, in the present in vitro study, antimicrobial activity of Alum as well as its Bhasma- Sphatika Bhasma was evaluated against total 10 organisms, viz., 4 gram negative [Escherichia coli (ATCC-10148), Klebsiella pneumoniae (ATCC-700603), Pseudomonas aeruginosa (Fishers Immuno Type IV), Salmonella typhi (NCTC-786)], 4 gram positive [Bacillus subtilis (ATCC-9372), Enterococcus faecalis (ATCC-29212), Methicillin Resistant Staphylococcus aureus (MRSA ATCC-25923), Sarcina lutea (NCTC-2470)] and 2 fungi [Aspergillus niger (ATCC-16404) and Candida albicans (ATCC-10231)] using various assays such as MIC, MBC/MFC and Agar Well Diffusion method. In general, MIC values of Sphatika Bhasma were lower than that of Alum. Alum and Sphatika Bhasma revealed broad spectrum antibacterial activities inhibiting gram positive as well as gram negative organisms and moderate antifungal activities. Furthermore, different combinations prepared from Alum (AL), Sphatika Bhasma (SB) and standard antibiotics were subjected to determine their combinatorial effect against 10 organisms using Agar Well Diffusion Assay. The combinations (AL + CP), (SB + CP) and (AL + SB + CP) displayed synergistic effect against P. aeruginosa. Antimicrobial and Antioxidant potential of Alum and Sphatika Bhasma could be attributed to their Phenolic content. Overall, Sphatika Bhasma exhibited better Antimicrobial and Antioxidant activities than Alum.