A quick and inexpensive staining method for vaginal smears.

Vaginal cytology is a commonly used method for diagnosis of sexual cycle phases in the rat, but all staining techniques are time consuming. A simple, easy and fast technique is reported here, that is based upon the use of a Lugol solution that allows precise identification of the sexual cycle day of the rat. Following this technique, samples are taken at 8:00 a.m. and a smear is made on the glass slide adding one drop of Lugol solution. This preparation is covered and seen directly under the optic microscope.