The aim of this double-blinded, randomized, placebo-controlled, multicenter study was to assess the general and cardiac safety of desloratadine syrup in children aged 6 months to less than 2 years. Children received desloratadine syrup (0.5 mg/mL; 1.0 or 1.25 mg orally once daily, depending on age) or placebo for 15 days. Safety evaluations (adverse events from diary cards, physical examination, vital signs, and electrocardiography [ECG]) were performed on days 8 and 15 (final visit). Two hundred fifty-five patients were enrolled; 253 received at least 1 dose of study medication and 241 (95%) completed 15 days of therapy. The most common treatment-related adverse events included mild to moderate irritability, diarrhea, somnolence, anorexia, increased appetite, insomnia, and fever. No clinically significant changes in vital signs were noted. There were no statistically significant differences in the changes from baseline between treatment groups in individual ECG parameters (ventricular rate, PR, QRS, QT, and QTc intervals) at any time point. Most Fridericia QTc and Bazett QTc values at end point remained within 10% of baseline values in both treatment groups. Short (15-day) courses of desloratadine syrup are safe and well tolerated in very young children (≥ 6 months to < 2 years of age) and do not significantly influence vital signs or ECG parameters. © Mary Ann Liebert, Inc.