Antibiotic choice for Streptococcus pneumoniae (pneumococcus) depends on illness severity, patient risk factors, allergy history, and local resistance patterns—so there is no single universally correct “one antibiotic” answer. Mild community-acquired pneumonia may be treated with appropriate oral agents, while severe cases can require IV therapy. Clinicians typically follow evidence-based pneumonia guidelines and local antibiogram data to select effective coverage. Incorrect selection or stopping therapy early increases the risk of treatment failure and antimicrobial resistance. If pneumococcal pneumonia is suspected, the safest path is a structured clinical evaluation and a tailored antibiotic plan with appropriate follow-up.