On an international basis, outpatient parenteral antimicrobial therapy (OPAT) varies greatly. There are cultural as well as economic issues which make it different in every country. In general, the duration of hospital stay varies with the outpatient resources available and the economic base for them. In some countries, there may not be money available for any intravenous antibiotics, even in the hospital. In addition, there are great differences in outpatient intravenous therapy, with infusion clinics proliferating in China, yet these are scarce in the UK. There is also considerable variation in the use of intramuscular compared with intravenous therapies. In Italy, intramuscular ceftriaxone is used more often than intravenous therapy. While ceftriaxone use is high in the US, its use is surpassed on a per capita basis by Italy, and it is most interesting that the rate of antimicrobial resistance is lower in Italy than in most other European countries. Whether this relates to outpatient use, parenteral use or other unknown factors is unclear. Obviously, further studies are necessary.