Purpose: To evaluate an injectable gel, recently proposed for the controlled release of "active oxygen" in periodontal pockets, compared to an antibiotic or an antiseptic gel, respectively. Methods: The antimicrobial activity, injectability, texture properties, swelling and water uptake of the gels were studied. Results: The "active oxygen" gel showed a bactericidal effect comparable to the two commercially available drug products (containing minocycline or chlorhexidine) on anaerobic periodontal pathogens and did not seem to affect aerobic strains. The gel was easy to inject and stable in an aqueous medium for several days. Texture analysis revealed potential gel fragility. Clinical significance: The investigated gel for local delivery of oxygen can help to selectively eradicate anaerobic bacteria associated with periodontitis and promote the recovery of a healthy-compatible oral flora.