Gallic acid (3,4,5‑trihydroxybenzoic acid; GA), a plant‑derived natural phenolic compound, has been reported to prevent the development and progression of various types of cancers. However, there has been little elaboration of the anticancer effects and underlying mechanisms of GA alone and/or in combination with cisplatin in non‑small cell lung cancer (NSCLC). The aim of the present study was to investigate the anticancer effects of GA on NSCLC A549 cells and its auxiliary effects on the anticancer activity of cisplatin. The results revealed that GA inhibited the proliferation and induced the apoptosis of NSCLC A549 cells in dose‑ and time‑dependent manners, which was associated with upregulated B‑cell lymphoma 2 (Bcl‑2)‑associated X protein (Bax) and downregulated Bcl‑2. Notably, the results also indicated that GA enhanced the anticancer effects of cisplatin in the inhibition of cancer cell proliferation and the induction of cell apoptosis following elevated Bax expression and suppressed Bcl‑2 expression. Furthermore, the results of the present study also demonstrated that GA exerted independent anticancer effects on NSCLC A549 cells, and facilitated the anticancer effects of cisplatin by modulating the JAK/STAT3 signaling pathway and downstream apoptotic molecules. These results may serve as a rationale for further basic studies and preclinical investigations on the anticancer effects of GA and its auxiliary effects on cisplatin function in human NSCLC.