• A dense degradation product film consisted of calcium phosphate compounds and magnesium hydrate formed on pure Mg surface immersed in artificial saliva.

• The degradation rate kept low and pH values insignificantly changed in the first 5 days of immersion, then increased after 6 days of immersion, finally stabilized after 10 days of immersion.

• Pure Mg exhibited desirable degradation resistance in artificial saliva, which provided magnesium-based materials with the potential to be used as esophageal stents.