Huelin Injection contains Benzathine penicillin G (24 lac units) as its active ingredient, a long-acting penicillin antibiotic utilized for the treatment of various bacterial infections. Benzathine penicillin G exhibits bactericidal activity by inhibiting bacterial cell wall synthesis, making it effective against susceptible strains of Streptococcus, Pneumococcus, and other gram-positive organisms. This formulation is particularly indicated for the treatment of streptococcal pharyngitis, syphilis, rheumatic fever prophylaxis, and certain skin and soft tissue infections. Due to its prolonged absorption and sustained serum levels, Huelin Injection is administered intramuscularly, providing therapeutic concentrations over an extended period, which enhances patient compliance by reducing dosing frequency. Prior to administration, it is essential to confirm the absence of hypersensitivity to penicillins to avoid severe allergic reactions. Caution is advised in patients with a history of penicillin allergy or those with renal impairment. Common adverse effects may include local injection site reactions, hypersensitivity responses, and, rarely, neurotoxicity at high doses. Huelin Injection should be used under strict medical supervision with appropriate diagnostic evaluation and monitoring to ensure efficacy and safety. It is contraindicated in patients with known penicillin hypersensitivity.