A total of 73 physicians (90%) replied. The largest differences arose in treating patients with intravenous versus per oral antibiotics, and treating as inpatients versus outpatients. In Finland, 50% of PTA patients aged >16 years were treated as inpatients and 50% as outpatients, whereas the respective quotas in Sweden were 9 and 91%, Norway 19 and 81%, and Denmark 33 and 67%. Of Finnish physicians, 30% treated their patients primarily with oral antibiotics, 70% with intravenous antibiotics; in Sweden 91 vs 9%, Norway 53 vs 47%, and Denmark 18 vs 82%. In Denmark, almost all patients were operated on immediately, whereas in the other three countries, especially Sweden, operations more often were performed after a recovery period. Combining metronidazole with penicillin or cephalosporins was most common in Denmark: 58% reported usage, compared with 30% in Finland, 16% in Norway, and 4% in Sweden.