PIP: There is increasing evidence that genital ulceration, including syphilis, chancroid, and herpes simplex type 2, increases susceptibility to HIV infection. It may be that the HIV penetrates more easily through ulcerated membranes or that the lymphocytes associated with the inflammatory response present target cells for HIV infection. There is also evidence that HIV-infected women with genital ulcers are themselves more infective due to shedding of the virus in the genital tract. Nonulcerative sexually-transmitted diseases have also been associated as cofactors of HIV infection. Programs for the control of sexually transmitted diseases should be strengthened and should focus on eliminating chancroid, which is easily treated with antibiotics. Patients with genital ulcer disease should receive counseling, so that they will know that untreated genital ulcers increase the risk of HIV infection.