The gastric mucosa protection effect of three natural plant extracts, Hericium erinaceus (HE), Centella asiatica (CA) and Amomum villosum (AV), were evaluated using the indomethacin damage model. Compared with a single extract, a combination of HE/CA/AV, especially with the ratios of 80:10:10, 45:45:10 and 45:10:45, showed significant synergistic effects for protection of the gastric mucosa with gastric ulcer inhibition rates of 97.8 ± 0.7%, 86.5 ± 2.8% and 86.1 ± 3.6%, respectively. Microscopic appearances of the gastric mucosa were carried out to help confirm the results.