Contouring injection is one of the most popular procedures in cosmetology, and its popularity is steadily increasing. Various available fillers allow successful correction of aesthetic defects and age-related changes considering individual characteristics of patients. Delayed inflammatory reactions are a rare undesirable phenomenon and often lead to diagnostic difficulties, especially after previous cosmetic procedures. Non-certified fillers complicate the situation. Many of these fillers are permanent that directly affects therapeutic strategy and prognosis. Therefore, every cosmetologist, dermatologist and plastic surgeon should be aware of the properties, characteristics and behavior in tissues of various fillers. The first part of review is devoted to classification of fillers and description of permanent microimplants.

Keywords. complications, permanent fillers, synthetic fillers, delayed inflammatory reaction, histology of fillers, granuloma