Polyphenols, a diverse group of plant-derived compounds found in foods like tea, berries, cocoa, and wine, have been studied for their antimicrobial properties. While they are not direct substitutes for antibiotics in the treatment of established bacterial infections, scientific research indicates that polyphenols can exert antimicrobial effects in vitro (lab studies) against a range of bacteria, including antibiotic-resistant strains. Mechanisms proposed include disrupting bacterial cell walls, inhibiting enzymes critical to bacterial survival, and interfering with bacterial communication systems (quorum sensing).

Some animal studies and limited clinical research suggest that certain polyphenols (e.g., epigallocatechin gallate from green tea, resveratrol from grapes, and curcumin from turmeric) may reduce the severity or incidence of infections, enhance the effects of conventional antibiotics, or help prevent the development of resistance. However, these effects are generally modest compared to standard antibiotics, and the majority of evidence comes from laboratory studies rather than large-scale human clinical trials.

As such, polyphenols are not considered clinical alternatives to antibiotics but are studied as adjuncts or preventive agents. The overall evidence base is limited, with a need for more robust, well-controlled human studies to validate efficacy and safety as antibiotic alternatives.