Cutaneous penetration of methyl nicotinate has been investigated in 20 women divided into reactors and non-reactors on the basis of response to 10% aqueous solution of lactic acid. The vasodilation induced was measured using a laser Doppler perfusion imager (LDPI) every 5 min for 1 h after application of methyl nicotinate. The intensity and duration of inflammation generated by methyl nicotinate were used to assess penetration of this chemical in persons with sensitive skin compared to those with normal skin. Significant differences were found between reactors and non-reactors. Reactors showed a significantly increased intensity of response to methyl nicotinate as early as 5 min after application, and for 30 min afterwards, though the duration of inflammation in these 2 groups was the same. Correlation between increased penetration of methyl nicotinate and skin response to lactic acid may suggest increased penetration of water-soluble chemicals in individuals with sensitive skin.