The effect of ethanol on the luminol‐dependent chemiluminescence and cAMP level in mice peritoneal macrophages was investigated. Ethanol was shown to inhibit the chemiluminescence of macrophages by acting both as a “trap” for active radicals and as a suppressor of the cellular functional activity. A short preincubation of macrophages with ethanol results in a dose‐dependent decrease of the chemiluminescent response to the stimulatory agent (opsonized zymosan). Ethanol was also shown to induce a peakwise rise of the intracellular cAMP after a 2‐min incubation. The observed effects are correlated both in time and concentration, which allows the presumption that inhibition of the functional activity of macrophages is mediated by the increase of the intracellular cAMP level. 1992 The Swiss Political Science Review