The food industry is developing new packaging systems (active packaging) through the incorporation of essential oils or their main compounds into the films. This could confer them the antimicrobial and/or antioxidant properties already extensively described for these substances, improving the shelf life of perishable food products. However, a safe range of concentrations for their use in active food packaging should be established to reach the market proposals and avoid risks for consumers. The present work reviews the scientific literature concerning these two properties together with the toxic effects induced by these substances on human cell lines.