Severe bacterial infections in children need prompt, appropriate antibiotic treatment. We report challenges observed within a prospective, cohort study on antibiotic efficacy in non-typhi Salmonella bloodstream infection (NCT04850677) in Kisantu district hospital (Democratic Republic of Congo). Children (aged > 28 days to < 5 years) admitted with suspected bloodstream infection (August 1, 2021 through July 31, 2022) were enrolled and followed until day 3 or discharge for non-typhi Salmonella patients. Antibiotics were administered to 98.4% (1,838/1,867) of children, accounting for 2,296 antibiotic regimens (95.7% intravenous, 4.3% oral). Only 78.3% and 61.8% of children were, respectively, prescribed and administered antibiotics on the admission day. At least one dose was not administered in 3.6% of children, mostly because of mismatch of the four times daily cefotaxime schedule with the twice-daily administration rounds. Inappropriate intravenous administration practices included multidose use, air-venting, and direct injection instead of perfusion. There was inaccurate aliquoting in 18.0% (32/178) of intravenous ciprofloxacin regimens, and thus administered doses were > 16% below the intended dose. Dosing accuracy of oral suspensions was impaired by lack of instructions for reconstitution, volume indicators, and/or dosing devices. Adult-dose tablets were split without/beyond scoring lines in 84.4% (27/32) of tablets. Poor availability and affordability of age-appropriate oral formulations contributed to low proportions of intravenous-to-oral switch (33.3% (79/237) of non-typhi Salmonella patients). Other quality issues included poor packaging, nonhomogeneous suspensions, and unsafe water for reconstitution. In conclusion, poor antibiotic products (no age-appropriate formulations, poor quality and access), processes (delayed prescription/administration, missed doses), and practices (inaccurate doses, [bio]safety risks) must be urgently addressed to improve pediatric antibiotic treatment.