Hyaluronic acid is a linear polysaccharide found in almost all vertebrate organs. The highest concentrations are found in soft connective tissues (umbilical cord, synovial fluid, skin) and the lowest in blood serum. Hyaluronic acid has been identified in all periodontal tissues, being particularly prominent in the non-mineralized tissues such as gingiva and periodontal ligament. Low quantities are to be found in mineralized tissues such as cementum and alveolar bone. Most of the cells have the ability to synthesize hyaluronic acid. Hyaluronic acid is biocompatible and non-immunogenic. It has an anti-inflammatory and bacteriostatic properties, and promotes healing. It has been in use in dental medicine since the beginning of the 21st century. In the treatment of periodontitis, it is applied topically in combination with non-surgical and surgical periodontal therapy and leads to significant clinical improvement. Topical application of hyaluronic acid gel has been observed to have a positive effect in patients with gingivitis. It inhibits the pathological effect of dental plaque on peri-implant tissue and improves soft tissue healing. Hyaluronic acid gel injections lead to a reduction of ‘black triangles’ even after a single application, but better and longer-lasting results are achieved by multiple injections of hyaluronic acid into the area of the interdental papilla. In the treatment of temporomandibular disorders, it leads to improved temporomandibular joint function and pain relief, but more research is needed to further investigate its application. In patients with recurrent aphthous ulcers, it is a good alternative to corticosteroids because it leads to faster healing, relieves pain and is safe for use in infants and pregnant women. Relief of symptoms has been observed in patients with burning mouth syndrome.