4-Methylsulfonyl-2-nitrobenzoic acid, also known as MS-2NB, phenol, or acid sulfo nitro, is a drug commonly used in children with febrile seizures. It works by reducing the frequency and severity of seizures. Dosage and administration for MS-2NB depend on various factors such as weight and other medications the child may be taking. Side effects of MS-2NB can include nausea, dizziness, and skin rash. It is essential to follow the prescribed dosage and consult a healthcare provider if any adverse reactions occur.