Objective The use of autologous platelet-rich gel (APG) is a relatively new technology and a promising treatment method for infections, which is currently being used by a variety of surgical specialties. The mechanism of antibacterialeffect of APG is not yet fully discovered. Subsequent evidence suggests that platelets have multi ple functional attributes inantimicrobial host defense (including the capacity to generate antimicrobial oxygen metabol ites and the antimicrobial peptides) and interact directly with microorganisms, contribute to clearance of pathogens from the blood. To investigate the bacteriostasis of APG against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa in vitro. Methods Platelet-rich plasma (PRP) and platelet-poor plasma (PPP) were obtained from whole blood of 17 healthy donors. APG was prepared by mixing PRP with bovine thrombin in a 10% calcium gluconate solution or bovine thrombin in a 10% calcium gluconate solution and apocynin (APG-APO). Antibacterial effects of APG, PRP, and APG-APO on Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa were evaluated by bacteriostasis assay. Results The culture results showed apparent decrease in the number of Staphylococcus aureus for both APG and APG-APO, which was maximal at first 4 hours and lasted to 24 hours and 8 hours, respectively; showing significant difference (P lt; 0.05) when compared APG with PRP and PPP, however no significant difference at first 8 hours (P gt; 0.05) and significant difference at 12 and 24 hours (P lt; 0.05) when compared APG with APG-APO; showing significant difference at first 4 hours (P lt; 0.05), no significant difference at 6, 8, 12, and 24 hours when compared APG-APO with PRP and PPP (P gt; 0.05). The bacteriostasis rates of APG and APG-APO were 27.36%-52.97% and 18.82%-51.52% against Escherichia coli, respectively; showing no significant difference (P gt; 0.05) when compared with PRP. The bacteriostasis rates of APG and APG-APO were less than 35% against Pseudomonas aeruginosa, showing no significant difference (P gt; 0.05) when compared with PRP; the bacteriostasis rates of PRP were less than 15% against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. Conclusion APG may have potential bacteriostatic effect against Staphylococcus aureus by platelet mediating. Either APG or APG-APO has no obvious bacteriostatic effect against Escherichia coli or Pseudomonas aeruginosa. PRP has no antibacterial activity against Staphylococcus aureus, Escherichia coli or Pseudomonas aeruginosa.