Cefepime is widely considered a safe and effective antibiotic, but it can have rare and serious side effects. We present a case of a 33-year-old female patient who developed severe and potentially life-threatening neutropenia after being on cefepime for 25 days. Despite extensive investigations, no other causes of neutropenia could be identified. Discontinuing the medication and administering a single dose of filgrastim produced a rapid and dramatic response. This case highlights the rare but serious risk of cefepime-induced neutropenia and underscores the need for clinicians to remain vigilant for this potential adverse effect. It is important to note that discontinuing the medication can rapidly reverse the effects, making timely recognition and intervention crucial for patient outcomes.