In this study, the nanosized spherical erythromycin capped gold nanoparticles (eryth-Au(0)NPs) were fabricated for the first time. After that, multiple techniques such as UV-Visible, FTIR, HR-TEM, and XRD were used to examine the Au(0)NPs. Finally, these eryth-Au(0)NPs were employed for a wide range of applications, such as catalysis, antibacterial, and anticancer activities. The eryth-Au(0)NPs had shown remarkable catalytic activity as a catalyst in the ∼99% fragmentation of ibuprofen and paracetamol in one minute. They were also easily recovered from the reaction mixture and were reused seven times with increased catalytic potential. The excellent antimicrobial properties of Staphylococcus aureus (S. aureus) and Salmonella typhi (S. typhi) were also revealed using the well diffusion method. In addition, TLR expression levels in SKBR3 cells were measured using qReal-time PCR (qRT-PCR). TLR3 expression was upregulated in the SKBR3 breast cancer cell line, while TLR2, TLR4, TLR5, and TLR9 expression was downregulated. Furthermore, the simultaneous overexpression of p53 and downregulation of NF-kB demonstrated anticancer efficacy in breast cancer cells. The recent advancements can also be used to protect the aquatic environment from drugs toxicity in wastewater and antimicrobial and anticancer activities using a simple, cost-effective, fast, and efficient reduction/degradation technique based on the catalytic potential of eryth-Au(0)NPs.