Atherosclerosis is a chronic inflammatory disease of the arterial wall. The expression of adhesion molecules in aortic smooth muscle cells facilitates the accumulation of transmigrated leukocytes within the atherosclerotic vascular wall. The stem of Akebia quinata (A. quinata) has previously been used as a crude drug for treating urinary disorders and inflammatory disease in Korea, China and Japan. In the present study, we investigated the effect of an A. quinata ethanol extract (AQEE) on the expression of adhesion molecules and cyclooxygenase-2 (COX‑2) in tumor necrosis factor α (TNF-α)-induced human aortic smooth muscle cells (HASMCs). The results of the present study demonstrated that AQEE attenuated intercellular adhesion molecule 1, E‑selectin and COX‑2 expression in TNF‑α-stimulated HASMCs and inhibited THP-1 cell adhesion to activated HASMCs. Furthermore, AQEE suppressed the TNF‑α induced phosphorylation of p38 mitogen-activated protein kinase (MAPK) and reduced nuclear factor κB (NF-κB; p65) nuclear translocation. The present study demonstrated that AQEE possesses anti‑inflammatory properties and regulates TNF-α-induced expression of adhesion molecules by inhibition of the p38 MAPK/NF-κB signaling pathway.