Introduction:Heparin is a sulfated polysaccharide belonging to the glycosaminoglycan family with strong anticoagulant activity. It has been widely used to maintain intravascular catheters in patients requiring intravenous medication. It is believed that heparin prevents thrombus formation in the intravascular catheter, but since the 1980s, the necessity of the heparin solution for peripheral intravenous catheter (PIVC) flushing has been questioned in several clinical trials. According to the Institute for Safe Medication Practices (ISMP), there are four special categories of High Alert Medications (HAMs), including heparin.Aim:The aim of this systematic review was to investigate the efficacy of normal saline versus heparin solution in maintaining the patency and functionality of the PIVC and avoiding complications.Methodology:A systematic review using PubMed and Cochrane Library databases was conducted. Original research studies of hospitalized patients with PIVC, regardless of age, published in English, over the last decade (2009-2019) were eligible for inclusion.Results:The review concluded in 10 studies that met the inclusion criteria. From these studies, it appears that it is not fully documented whether the normal saline (N/S 0,9%) is superior to heparin solution (H/S) in the flushing of the PIVC for maintaining its patency and prevent complications. Researchers tend to support the use of N/S 0,9% due to safety, error avoidance, efficiency, ease of use and cost-effectiveness. Concern about the possible complications of the heparin solution was the cause of guidelines development for N/S 0,9% in countries such as Australia.Conclusions:The use of normal saline seems to outweigh the heparin solution in maintaining the patency of PIVC.