With the exception of AHAs (glycolic acid and lactic acid), all of the ingredients used for this set are scored by the EWG (a non-profit that rates the toxicity of ingredients found in skincare) as 1-2, which is the lowest toxicity rating they give out. Even with AHAs, we made sure to use them at low hazard levels so that they would be effective on your skin minus harsh irritation. 

Toner Ingredients (12): Water, Glycerin, 1,2-Hexanediol, Propanediol, Glycolic Acid, Sodium Citrate, Lactic Acid, Tricholoma Matsutake Extract, Ethylhexylglycerin, Hydrolyzed Cider Seed Extract, Rhododendron Chrysanthum Leaf Extract, Tocopherol

Serum Ingredients (14): Water, 3-O-Ethyl Ascorbic Acid, Propanediol, Butylene Glycol, 1,2-Hexanediol, Ascorbic Acid, Hydroxyethylcellulose, Sodium Hyaluronate, Citric Acid, Ferulic Acid, Tocopherol, Ethylhexylglycerin, Coptis Japonica Root Extract, Trisodium Ethylenediamine Disuccinate