Recently, an update of the IDSA guidelines for the treatment of complicated intraabdominal infections has been published. No guideline can cater for all variations in ecology, antimicrobial resistance patterns, patient characteristics and presentation, health care and reimbursement systems in many different countries. In the short time the IDSA guidelines have been available, a number of practical clinical issues have been raised by physicians regarding interpretation of the guidelines. The main debatable issues of the new IDSA guidelines are described as follows: The authors of the IDSA guidelines present recommendations for the following subgroups of "complicated" IAI: community-acquired intra-abdominal infections of mild-to-moderate and high severity and health care-associated intra-abdominal infections (no general treatment recommendations, only information about antimicrobial therapy of specific resistant bacterial isolates). From a clinical point of view, "complicated" IAI are better differentiated into primary, secondary (community-acquired and postoperative) and tertiary peritonitis. Those are the clinical presentations of IAI as seen in the emergency room, the general ward and on ICU. Future antibiotic treatment studies of IAI would be more clinically relevant if they included patients in studies for the efficacy and safety of antibiotics for the treatment of the above mentioned forms of IAI, rather than conducting studies based on the vague term "complicated" intra-abdominal infections. - The new IDSA guidelines for the treatment of resistant bacteria fail to mention many of new available drugs, although clinical data for the treatment of "complicated IAI" with new substances exist. Furthermore, treatment recommendations for cIAI caused by VRE are not included. This group of diseases comprises enough patients (i.e. the entire group of postoperative and tertiary peritonitis, recurrent interventions in bile duct surgery or necrotizing pancreatitis) to provide specific recommendations for such antimicrobial treatment. - A panel of European colleagues from surgery, intensive care, clinical microbiology and infectious diseases has developed recommendations based on the above mentioned clinical entities with the aim of providing clear therapeutic recommendations for specific clinical diagnoses. An individual patient-centered approach for this very important group of diseases with a substantial morbidity and mortality is essential for optimal antimicrobial treatment.