Question 26 of the February 15, 1998, “Clinical Quiz” (page 626), pertaining to the item in “Tips from Other Journals” titled “Diagnosis, Treatment and Prevention of Giardiasis,” was written incorrectly. The question should have asked which one of the five listed agents is commonly used in the United States as a single course of treatment for giardiasis in an adult patient who is not pregnant. The correct answer remains D. In the same issue, question 29, which refers to the item in “Tips from Other Journals” titled “Antibiotic Utilization in Hospitalized Elderly Patients,” was misleading because a key sentence was left out of the Tip (page 844). The missing sentence, which should have opened the fourth paragraph, reads as follows: “[The] ability to diminish antibiotic expenditures was in large part related to aggressive conversion of parenteral to oral formulations.” The correct answer remains A.