Erythromycin and co-amoxiclav are two commonly prescribed antibiotics in aesthetic practice, with their indications including acne vulgaris, rosacea, cellulitis and urinary tract infections. However, they are also useful in treatment of skin and soft tissue infections which may occur following aesthetic procedures. Erythromycin is a macrolide antibacterial with a spectrum similar, however not identical to penicillin. Erythromycin is therefore commonly used in penicillin-allergic patients. Co-amoxiclav (brand name Augmentin) is a combination of amoxicillin, broad-spectrum penicillin and clavulanic acid, a beta lactamase inhibitor. This combination increases the spectrum of action the antibiotic has while regaining its efficacy against the bacteria previously amoxicillin-resistant due to the production of beta-lactamase. Deciding on an antibiotic to use in each case can often be a difficult choice to make. The clinician must first consider two important factors: the patient and the known or likely causative organism. A thorough understanding of these antibiotics ensures safe prescribing.