The effects on the vaginal epithelium of three different menstrual tampons in normal conditions of use were studied in 41 women during the menstrual period. The vaginal epithelium was studied in a total of 123 cycles at a structural and ultra-structural level with colposcopy, vaginal smear and biopsy on TEM and SEM. One of the three tampons studied showed a lower level of abnormalities on colposcopy (36.6% vs. 56.1% vs. 68.3%), with an inverse correlation between the severity of the dryness and the quantity of blood absorbed by the tampon (4.2 g when the colposcopy was normal vs. 1.8 g in case of severe dryness). Cytology is not a good test for assessing the effects of tampons because of the high rate of acellular and uninterpretable samplings. The biopsy effects were defined according to their depth in the epithelium. The same tampon showed the lowest level in biopsy abnormalities. No correlation was found between severity of the colposcopy and biopsy results. Colposcopy can demonstrate the degree of severity of dryness or any other effect, but biopsy only confirms the effect and does not correlate the degree of severity. Materials and designs of tampons can play a role in reducing the drying effects to the vaginal epithelium.