Emulsifiers are substances that enable the formation of a stable emulsion from two or more immiscible components in a mixed liquid. The principle of their action lies in the emulsification process, where the dispersed phase is distributed in the form of fine droplets (micron-sized) within the continuous phase. Emulsifiers reduce the interfacial tension between the components in the mixed system and form a robust film on the surface of the droplets or create an electrical double layer due to the charge provided by the emulsifier. This prevents the droplets from coalescing and maintains a uniform emulsion. From a phase perspective, emulsions remain heterogeneous systems. The dispersed phase in an emulsion can be either aqueous or oily, with the majority being oily; the continuous phase can be either oily or aqueous, with the majority being aqueous. Emulsifiers are a type of surfactant, with molecules containing both hydrophilic and lipophilic groups. To indicate the hydrophilicity or lipophilicity of an emulsifier, the "Hydrophile-Lipophile Balance (HLB) value" is commonly used. The lower the HLB value, the stronger the lipophilicity; conversely, the higher the HLB value, the stronger the hydrophilicity. Different emulsifiers have varying HLB values, and to achieve a stable emulsion, it is essential to select the appropriate emulsifier.