Panty liners are used to absorb light menstrual flow, vaginal discharge, or urine leakage, or to maintain a clean, dry feeling. Allegations that panty liners may trap heat and moisture to promote vulvovaginal candidiasis (VVC) or promote colonization by microbes that contribute to urinary tract infections appear to be unfounded. As reviewed herein, measurements of the impact of panty liners on skin temperature and skin surface moisture had no clinically meaningful effect on cell densities of genital microflora. Epidemiological investigations of a potential link to VVC were either negative or were inconclusive because of confounding factors. Although enteric microbes reside on the vulva and perineum, no evidence exists that panty liner use promotes urethral colonization by enteric microbes. Moreover, a series of 13 randomized prospective trials of panty liners or ultra-thin pads demonstrated no clinically significant adverse effects either on the skin or on isolation frequencies or cell densities of representative genital microflora. Post-market surveillance systems suggest a low incidence of complaints. Evidence from vulvar clinic patients reveals no significant contribution of these products to persistent vulvar symptoms. Taken together, the scientific evidence supports the conclusion that panty liners are safe when used as intended and do not promote VVC or urinary tract infections.