A comparative evaluation of the safety and efficacy of cefotetan and cefoxitin in surgical prophylaxis. Safety and efficacy were evaluated and compared retrospectively in 77 patients who received cefotetan (CTN) and 51 patients who received cefoxitin (CFX) for surgical prophylaxis. Both groups were similar with respect to age and gender. Surgical procedures were similar between groups (e.g., obstetric/gynecologic, renal transplant, colon, exploratory laparotomy, gastroduodenal, hernia repair). Postoperative infectious complications were more common in the CTN group (11.6 percent [9/77]) than in the CFX (7.8 percent [4/51]) group; however, this difference was not statistically significant. A higher incidence of wound infections was noted in the CTN group (5.2 percent [4/77]) than in the CFX group (2.0 percent [1/51]); this difference was also not significant. Patients receiving immunosuppressive therapy were more likely to develop infectious complications when CTN was used for prophylaxis (p = 0.0001). Clinically significant blood loss was not noted during surgery. Elevations in prothrombin times (greater than 1 sec) occurred in 27.3 percent (3/11) of CTN and 11.1 percent (1/9) of CFX patients (not significant). Except for the small subset of patients receiving concomitant immunosuppressive therapy, CTN appeared to be as safe and effective as CFX when used for surgical prophylaxis. Although not statistically significant, the increased incidence of wound infections in the CTN-treated patients requires further study in a prospective randomized comparison. 