Intravenous (IV) fluid is frequently used to treat patients who have been admitted with an acute infection; among these patients, some will experience pulmonary congestion and will need diuretic treatment. Consecutive admissions to the Internal Medicine Department of patients with an acute infection were included. Patients were divided based on IV furosemide treatment within 48 h after admission. A total of 3556 admissions were included: In 1096 (30.8%), furosemide was administered after ≥48 h, and in 2639 (74.2%), IV fluid was administered within <48 h. Mean age was 77.2 ± 15.8 years, and 1802 (50.7%) admissions were females. In a multivariable analysis, older age (OR 1.01 [95% CI, 1.00–1.01]), male gender (OR 0.74 [95% CI, 0.63–0.86]), any cardiovascular disease (OR 1.51 [95% CI, 1.23–1.85]), congestive heart failure (CHF) (OR 2.81 [95% CI, 2.33–3.39), hypertension (OR 1.42 [95% CI, 1.22–1.67]), respiratory infection (OR 1.38 [95% CI, 1.17–1.63]), and any IV fluid administration (OR 3.37 [95% CI, 2.80–4.06]) were independently associated with furosemide treatment >48 h after hospital admission. In-hospital mortality was higher in patients with furosemide treatment (15.9% vs. 6.8%,p< 0.001). Treatment with furosemide in patients admitted with an infection was found to be associated with prolonged hospital stay and increased in-hospital mortality.