In fact, in clinical practice, both erythromycin ointment and Bactrim ointment belong to the antibiotic class of drugs, and it is usually sufficient to apply one of them, not both together. First of all, when erythromycin ointment or Bactrim ointment is needed in clinical practice, it is often combined with obvious skin infections. For example, in patients with acne, eczema, or herpes zoster, if there is an obvious infection, applying erythromycin ointment or Bactrim ointment is not effective. It is not recommended to apply it directly with another antibiotic ointment. Instead, patients are advised to take antibiotics orally or intravenously to strengthen the anti-infection treatment. Patients who apply erythromycin ointment or Bactrim ointment, their antibacterial spectrum coverage is more or less the same.