Zeolites are porous mineral with high absorption and ion-exchange capacity. Their molecular structure is a dense network of AlO4 and SiO4 that generates cavities where water and other polar molecules or ions are inserted /exchanged. There are several synthetic or natural occurring species of zeolites with unique and outstanding physical and chemical properties which make them extremely useful in various fields including agronomy, ecology, manufacturing and industrial processes. Recently, a more specific application of naturally occurring zeolite, clinoptilolite, has been studied in veterinary and human medicine as an excellent detoxifying, antioxidant and anti-inflammatory agent. The objective of the present study is to evaluate antioxidant activities of natural and synthetic zeolites. The In vitro antioxidant activity of zeolites is assessed against hydrogen peroxide (H2O2) DPPH, 1,1-diphenyl-2-picryl-hydrazyl free radical (DPPH) scavenging using standard protocols. Synthetic zeolite showed higher antioxidant activity than natural zeolite. It can be concluded that the antioxidant role of zeolites is based on the ability to reduce lipid peroxidation, free radicals levels and to increase total antioxidant status (TAS) in serum.