Carboxymethycellulose is a compound used to treat dry eyes and soothe eye irritation. The compound is a cellulose derivative consisting of cellulose backbone along with glucopyranose monomers and their hydroxyl groups bound to carboxymethyl groups. As a food additive, it is used as a thickener or to stabilize processed foods as an emulsifying agent. Carboxymethycellulose is also the primary polymer found in artificial tear products with the ability to provide moistening to dry eyes while adhering well to mucous tissue. As a salt, Sodium carboxymethylcellulose is the most commonly used salt. It is added in food products as a viscosity modifier or thickener and emulsifier. Sodium carboxymethylcellulose is the most commonly used salt substitute.