Clove oil, OC for short, is usually dropped on cotton balls to relieve the pain of periapical periodontitis. Camphorphenol, abbreviated as CP, is coated on cotton twist, sealed after root canal treatment, and has less irritation. It is used to treat apical inflammation or pulpitis. Formaldehyde cresol (FC for short) is used in root canal therapy. After root enlargement, it is coated on a cotton swab and sealed. It is irritating and suitable for apical inflammation with large shadow area. There are generally two kinds of pulp deactivators: deciduous tooth deactivator (slow type) and arsenic deactivator (fast type), both of which are used to inactivate pulp. The former is usually taken out after seven to ten days of follow-up, while the latter is usually taken out in two to three days; There is also iodine glycerin, which is used to apply medicine after periodontal irrigation; Iodophenol, used to rinse periodontal abscess or burn gums after severe periodontitis, has hemostatic and anti-inflammatory effects.