The Italian goddess Mephitis was worshipped mainly in central and southern Italy between the 7th century BC and the 2nd century AD. The etymology of her name indicates liminal and mediating aspects. We can find evidence of other gods being worshipped in her cult places such as Jupiter, Mars, and Hercules. Mephitis has been linked to Leukotea, Venus, Diana, and Juno. The goddess was deprecated in the minds of Roman authors due to a negative association with sulphurous fumes in Valle d'Ansanto. I researched the way the cult of Mefitis was spread and I answered how and why this cult was changed. For this purpose, I described the literary and epigraphic sources and her cult places in Italy. The inscriptions from Mefitis' cult places contain mostly Oscan names of worshippers. A few of them were among the urban elite. The names of gentes are repeated in a few places, for example gens Mammia is found in Pompei and Potentia. The members of Oscan gentes perhaps carried the cult of the goddess to other cities and were adapted there to new circumstances. In Capua, the goddess appears at the temple of Diana and in Pompei she was identified with the figure of Venus Pompeian, who perhaps took over from her the epithet Fisica, appearing by the name of Mefitis already in Rossano di Vaglio and Grumentum. In the sanctuary of Ansanto, her original figure as the protector of fields (expressed in the epithet arva) was changed to the deity of sulphurous fumes and that figure of the goddess prevailed in the later literary sources. The figure of Mefitis is complicated and multipronged. It seems that every cult place exposed different aspects of the goddess.