Use of prophylactic antibiotics in clean surgery is still controversial. We reviewed the literature of the last 10 years to identify the best way to approach clean surgery. The question is more important for patients undergoing breast surgery. The presence of an infected breast wound delays the beginning of postoperative adjuvant anticancer therapy: there is good evidence to suggest that delayed adjuvant therapy compromises the outcome for patients in terms of both local control and survival. There are several clinical trials that have addressed the efficacy of prophylactic antibiotics for patients undergoing breast surgery and hernia repair. Platt et al assessed the efficacy of preoperative antibiotic prophylaxis in a clinical trial of 1218 patients undergoing clean surgery with an absolute reduction rate of 39% in wound infections. Gupta et al reported no influence on the incidence of infective complications by antibiotic prophylaxis in 357 patients undergoing elective breast surgery. Like breast surgery, use of prophylaxis in hernia repair is not clear: a prospective, randomized, double-blind, multicenter study of 619 patients assessed no benefit of antibiotic prophylaxis. On the other hand Lewis et al reported a 75% reduction of infections in low-risk patients when a single dose of cefotaxime was used in clean operations. A particularly interesting point is the use of prosthetic mesh in hernia repair and primary reconstructive surgery in breast surgery. Amland et al reported a significant reduction of the incidence of wound infections in a group of patients undergoing reconstructive breast surgery, receiving azithromycin vs placebo (5% vs 20%). In hernia repair we stress the need to prevent wound infections: currently Liechtestein's technique is widely performed all over the world. Mesh infection is an unpleasant event that requires prosthesis removal. The lack of conclusive studies about antibiotic prophylaxis in clean surgery suggests that a single-dose of cephalosporin at the induction of anesthesia may be prudent. This procedure is certainly inexpensive and safe and, more importantly, probably does not have an impact on antibiotic resistance.