ABSTRACTThis study attempted to determine whether a prior period of “stress” would elicit the sensitization reaction of the skin to topically applied chemical agents. A subthreshold concentration of 1‐chloro‐, 2‐4, dinitrobenzene (DNCB) was applied to the skin of 40 guinea‐pigs, 20 of which had been subjected to repetitive electrical shocks throughout the previous 15 minutes. They were examined 24 hours later, and were retested with DNCB at another site after 9 days for signs of delayed sensitization. The stressed animals exhibited a more severe contact‐reaction (p<. 01) after the induction test and also after the