Safety and Tolerability of the Vaginal Gel PRO 2000/5

Inclusion Criteria Volunteers may be eligible for this study if they: * Are female and 18-45 years of age. * Are willing and able to complete daily study records. * Are willing to undergo clinical exams and testing. * Either have regular menstrual periods or do not menstruate due to use of hormones. * Agree to stop using female barrier methods of birth control during the study. * Additionally, volunteers may be eligible for HIV-negative groups in this study if they: * Have not changed their use of hormonal birth control over the last 3 months. * Are HIV-negative. * Have a single male partner at low-risk for HIV infection and agree that he can be asked for his consent. * Agree to the following: To have vaginal intercourse 2 or more times a week; to use condoms provided by the study for each act of intercourse; to use the gel as directed; not to be in similar studies; not to receive oral sex; not to use IV drugs, except for medical treatment; not to use any other vaginal products; not to douche; and not to use vaginal drying agents. * Additionally, volunteers may be eligible for the HIV-positive group in this study if they: * Are HIV-positive. * Have a CD4 count greater than 200 cells/mm3. * Have a normal Pap smear at screening. * Are on stable anti-HIV drug therapy. * Agree to have no sexual intercourse during the study. * Have HIV care by qualified medical caregivers. * Agree to allow study staff access to their HIV medical care information. * Agree to the following: To use the gel as directed; not to use IV drugs other than for medical treatment; not to use any other vaginal products; not to participate in similar studies; not to receive oral sex; not to douche; and not to use any vaginal drying agents. Exclusion Criteria Volunteers will not be eligible for this study if they: * Are menopausal. * Have certain liver, kidney, or blood problems. * Have genital problems such as sores. * Are allergic to anything used in the study, including latex. * Have used spermicides or condoms treated with spermicides within the week before enrollment. * Have been in another drug study within the past 30 days. * Have participated in this trial before and study gel has been permanently discontinued. * Have had an IUD or begun using hormonal birth control, or had an abnormal Pap smear, a pregnancy, an abortion, gynecologic surgery, breakthrough menstrual bleeding, or vaginal bleeding during or following sexual intercourse, in the last 3 months. * Have had or received treatment for sexually transmitted diseases in the past 3 months. * Show signs, on a pelvic exam, indicating a sexually transmitted disease or other genital tract problems. * Used IV drugs, except for medical reasons, within the past year. * Received antibiotics in the last 14 days. * Have had a reaction to an anticoagulant (such as warfarin or heparin). * Are pregnant or breast-feeding. * Have a positive urine culture.