The effects of water-based speculum lubricants on both conventional Papanicolaou smears and liquid-based Papanicolaou tests have been well documented. However, studies are lacking concerning the effects on these tests of personal lubricants and/or vaginal medications. Lubricants containing "carbomers" or "carbopol polymers" are known to interfere with ThinPrep® Papanicolaou test processing. Many over-the-counter products that advertise effects lasting several days may contain these substances. This study tests 2 popular personal lubricants (KY Warming Liquid [Johnson & Johnson, New Brunswick, NJ] and Replens [KoRa Health Care, Swords, Ireland]) and one yeast medication (Monistat 7, McNeill-PPC, Inc., Skillman, NJ) for interference on ThinPrep® Papanicolaou tests. The residual specimens from 270 ThinPrep® vials were combined to form 100 homogenous ThinPrep® Papanicolaou specimens. Nine groups of 10 vials were then contaminated with 20 μL, 100 μL, and 500 μL of each of the 3 products. One group of 10 vials served as control. Cell counts were performed after processing the specimens onto slides, and the results were recorded. KY Warming Liquid had no effect at any volume of contamination. Replens caused a drastic reduction in cellularity at even the lowest volume. Monistat 7 reduced cellularity incrementally as the volume increased. The potential exists for some over-the-counter lubricants and vaginal medications to interfere with the ThinPrep® Papanicolaou test.