In guided tissue regeneration, there is a number of four essential biological principles under the PASS acronym: (a) Primary closure of the surgical wound to allow uninterrupted healing; (b) Angiogenesis for adequate blood supply (supply of nutrients, as well as cell types that facilitate healing); (c) maintaining the Space for bone neo-formation, while blocking the proliferation of soft tissues and (d) wound Stability to allow blood clots to form [5]. The idea that the repopulation of cells on the root surface after periodontal surgery determines the nature of the attachment that will form is generally accepted. After the periodontal debridement, with or without open flap procedure, the root surface will be repopulated by the fastest cells, which were epithelial cells [6]. Barrier membranes placed over areas of tissue defect have as their main purpose the blocking of cell invasion from the gingival epithelium and connective tissue [7]. Barrier membranes require full in situ functionality for 4-6 weeks for periodontal tissue regeneration and 16-24 weeks for bone growth [8]. There are a number of mandatory requirements for a barrier membrane to be used successfully in guided regenerative therapies; these requirements include (a) good mechanical isolation, occlusion and blocking capabilities; (b) to be biologically active; (c) to be biocompatible; (d) to exhibit tolerance to exposure and (e) to be biodegradable [9]. Moreover, barrier membranes should have adequate porosity to prevent the excessive penetration of oral keratinocytes into the bone defect on one side but also to allow neovascularization and bone formation in the connective tissue part of the membrane [10]. It should also be easy to manipulate the membrane, to stabilize it at the site without damaging it [11]. To date, there is no commercially available membrane that meets all these parameters at optimum capacity, but recent developments in membrane production technology are trying, through various innovative forms, to meet as wide a range of characteristics as necessary to achieve predictable surgical results. To meet some of these requirements, various techniques and materials have been developed to generate tissue neo-formation. They can be divided according to the biodegradability of the base material into absorbable membranes and non-absorbable membranes [12] (Figure 1). The use of absorbable membranes is extremely widespread due to their advantages, but in clinical situations of significant tissue loss, the use of non-absorbable membranes is often still preferred [13]. Another classification of barrier membranes includes the first generation of membranes (non-absorbable), second generation (absorbable) and third generation (membranes as a product of tissue engineering) [14]. Figure 1: Main categories of barrier membranes used in guided tissue regeneration. e-PTFE: expanded polytetrafluoroethylene; d-PTFE: high density polytetrafluoroethylene; PLA: polylactic acid; PGA: polylgactic acid; PCL: polycaprolactone; PLGA: poly-lactic-co-glycolic acid PLCL: poly-lactic-co-caprolactone acid. We believe that a better understanding of the various types of membranes available and their properties is absolutely necessary in making clinical decisions. Thus, this review proposes a synthesis of the types of barrier membranes available and their characteristics; in addition, this paper presents future trends in the development of the field of barrier membranes, as well as some allergological aspects of membrane usage.