Therapy to eradicate pharyngeally carried group A streptococci (GAS) has increasingly been used in the management of institutional outbreaks and is now recommended for household contacts of patients with streptococcal toxic shock syndrome. In this randomized, controlled trial, contacts of patients with GAS infections were screened for pharyngeal GAS colonization. Those whose cultures were positive were randomized to receive either cefixime (8 mg/[kg.d]; maximum 400 mg) or rifampin (20 mg/kg; maximum, 600 mg) once a day for 4 days. Two to five days following completion of therapy, repeated cultures were negative for 13 (38%) of 34 rifampin recipients and 71 (77%; 95% CI, 69%-85%) of 97 cefixime recipients. At 10-14 days after treatment, only 53% of cefixime recipients remained culture-negative. Rates of successful clearance improved with increasing age (P < .01); among 17 adults who received cefixime, the success rate was 94%. Four days of therapy with rifampin is not effective for eradication of pharyngeally carried GAS. Four days of therapy with cefixime may be effective for adults, but further studies are needed.