There are many reasons, but most of them are due to alcohol, salicylic acid and other ingredients. Alcohol is the most common and most abundant ingredient in lotions and toners. Alcohol can calm, reduce inflammation and help absorption. Some specific ingredients cannot be dissolved in water and must be dissolved by alcohol. Alcohol is the mildest alcohol solvent. However, alcohol is highly volatile and may cause a pungent sensation in the eyes. There are also salicylic acid and some fruit acids, which are highly acidic, and the eyes are the weakest part of the human body. When the pH value changes slightly, the skin around the eyes will quickly feel it. These ingredients are mostly found in rejuvenation. in skin and acne products.