Herpes simplex encephalitis (HSE) is a rare but serious condition caused by the herpes simplex virus (HSV), typically HSV-1. It leads to inflammation of the brain, which can result in symptoms such as fever, headache, confusion, and seizures. HSE can progress rapidly and may cause long-term neurological damage or even death if not treated promptly. Diagnosis often involves imaging tests like MRI and analysis of cerebrospinal fluid through a lumbar puncture. Treatment usually includes antiviral medications, which are most effective when started early. Early recognition and intervention are crucial for improving outcomes in affected individuals.