Perilla leaves are known to be a rich source of polyphenols, which have been shown to exhibit various biological effects. This study aimed to compare the bioefficacies and bioactivities of fresh (PLEf) and dry (PLEd) Thai perilla (Nga-mon) leaf extracts. Phytochemical analysis indicated that both PLEfand PLEdwere abundant in rosmarinic acid and bioactive phenolic compounds. PLEd, which had higher levels of rosmarinic acid but lower levels of ferulic acid and luteolin than PLEf, exhibited greater effectiveness in a free radical scavenging assay. Furthermore, both extracts were found to suppress intracellular ROS generation and exhibit antimutagenic activity against food-borne carcinogens inS. typhimurium. They also attenuated lipopolysaccharide-induced inflammation in RAW 264.7 cells by inhibiting the expression of nitric oxide, iNOS, COX-2, TNF-α, IL-1β, and IL-6 through the suppression of NF-κB activation and translocation. However, PLEfexhibited a higher ability to suppress cellular ROS production and higher antimutagenic and anti-inflammatory activities than PLEd, which can be attributed to its combination of phytochemical components. Overall, PLEfand PLEdhave the potential to serve as natural bioactive antioxidant, antimutagenic, and anti-inflammatory agents to achieve potential health benefits.