Cicatrix is a secondary morphological element caused by a mass lesion of connective tissue at the damaged site. The question whether it is a physiological norm or a pathology is still open to debate. The paper presents the data on pathogenesis and stages of scarring. The issues of classification, clinical signs, differential diagnosis and therapeutic correction of cicatricial skin changes. The authors draw attention to the fact that the choice of treatment must take into account not only the presence and the size of a cicatricial deformity, but also the extent of its influence on patient's physical, psychological and social adjustment. Hyaluronidase enzyme is the most general agent for treating pathologies of connective tissues. The results of treating 120 patients of different age with hypertrophic and keloid scars using ultraphonophoresis, photophoresis, intrascar and intramuscular injections of Longidaza. The comparative description of the effect of different methods of Longidaza administration on clinical signs of scarring is provided. For fresh scars, Longidaza is sufficiently efficient in different ways of administration. The best effect for treating old (over 1 year-old) hypertrophic and keloid scars was observed for intrascar administration of Longidaza.