Alcohol, iodophor, iodine, hydrogen peroxide …… believe that many people are not unfamiliar with these topical drops, so how do these types of drops actually distinguish and how to use them safely? Alcohol Alcohol is widely used, 75% alcohol can be used for skin disinfection, medical device disinfection, iodine deiodination, etc. The outside of shallow wounds or sutures can be disinfected with alcohol. Deeper wounds or wounds in mucous membrane areas are not suitable for disinfection with alcohol because alcohol is more irritating and can easily cause pain, especially not for children and young children who have poor tolerance. It is worth noting that 75% alcohol can be used to disinfect the skin before insulin injection (wait for the alcohol to evaporate before injecting insulin to avoid pain), and iodine-containing disinfectant should not be used, otherwise it will affect the absorption of insulin. 2. iodophor and iodine The active ingredients of iodophor and iodine are both iodine, and the solvents of both are water and alcohol respectively. Iodophor has a broad-spectrum bactericidal effect and can kill bacterial propagules, fungi, protozoa and some viruses. It can be used for disinfection of skin and mucous membranes, as well as for treatment of burns and skin mold infections. Compared with alcohol, iodophor causes less painful irritation and is easily accepted by patients, and is so versatile and effective that it basically replaces alcohol and other skin and mucous membrane disinfectants. In addition, low concentration iodophor is a light brown solution that does not easily contaminate clothing. Iodine, also known as tincture of iodine, usually refers to a disinfectant solution consisting of a mixture of 2% to 7% iodine monomers and potassium iodide (or sodium iodide) dissolved in alcohol and water, which has a powerful pathogen-killing effect and can be used to treat a variety of bacterial, fungal, and viral infectious skin diseases. Doctors for after wiping iodine and then wipe with 75% alcohol is mainly for deiodination, so as not to burn the skin with iodine. Several precautions should be taken when applying iodine: ① it should not be used over a large area to prevent iodine poisoning due to absorption of large amounts of iodine; ② it is not advisable to use iodine with too high a concentration as it may cause burns and dermatitis; ③ iodine should not be used for disinfection of broken skin and mucous membrane areas such as the eyes and mouth. Hydrogen peroxide, i.e. hydrogen peroxide, has a medical concentration of ≤ 3 % because of its strong oxidizing properties and is mainly used for wound irrigation or otitis media disinfection. The “bubbling” characteristics of hydrogen peroxide, medically known as “primary ecological oxygen”, is the “power” to kill bacteria. The bubbles produced by applying it locally can loosen the blood clots, pus and adherent necrotic tissues in wounds and make them easy to peel off, which is suitable for infected wounds. After rinsing the wound with hydrogen peroxide, it is recommended to rinse it again with saline.