Advances in the understanding of acute otitis media (AOM), lessons learned from antibacterial trials, and the emergence of pathogens with decreased susceptibility to commonly used antibiotics explain the need to redefine the role of tympanocentesis. The diagnostic value of tympanocentesis at baseline to establish the bacterial cause of AOM is well accepted. However, relevant ethical and scientific arguments conclude that repeat (or double) tympanocentesis cannot be recommended as routine procedure, either for the individual patient or for each treatment trial. Relevant aspects on trial design for AOM, with special emphasis on the value of double tympanocentesis, are reviewed.