The question itself of what drug is preferred for penicillin allergy has two possibilities, which are allergy in drug use and skin test allergy, as follows: i. Allergy in drug use: when a patient has an allergy in the course of penicillin use and resuscitation is performed, epinephrine intramuscular injection is preferred in this case. II. Allergy during skin test: If a patient develops an allergy during the penicillin skin test, this situation means that the next step is to consider what antibiotic to choose. For patients under 18 years old, often macrolide antibiotics are preferred when penicillin is allergic, such as azithromycin, roxithromycin, etc. are commonly used. If the infection is more severe, antibiotic escalation is often required. For patients over 18 years of age, it is recommended that quinolones are preferred, such as moxifloxacin, ofloxacin and so on, which are commonly used. In conclusion, penicillin allergy needs to be decided on a case-by-case basis to determine what kind of medication to choose.