The Centers for Disease Control and Prevention (CDC) recently published updated guidelines that provide new strategies for the prevention and treatment of sexually transmitted diseases (STDs). Patient education is the first important step in reducing the number of persons who engage in risky sexual behaviors. Information on STD prevention should be individualized on the basis of the patient's stage of development and understanding of sexual issues. Other preventive strategies include administering the hepatitis B vaccine series to unimmunized patients who present for STD evaluation and administering hepatitis A vaccine to illegal drug users and men who have sex with men. The CDC recommends against using any form of nonoxynol 9 for STD prevention. New treatment strategies include avoiding the use of quinolone therapy in patients who contract gonorrhea in California or Hawaii. Testing for cure is not necessary if chlamydial infection is treated with a first-line antibiotic (azithromycin or doxycycline). However, all women should be retested three to four months after treatment for chlamydial infection, because of the high incidence of reinfection. Testing for herpes simplex virus serotype is advised in patients with genital infection, because recurrent infection is less likely with the type 1 serotype than with the type 2 serotype. The CDC guidelines also include new information on the treatment of diseases characterized by vaginal discharge.