Abstract Skin tests and leukocyte histamine release (LHR) were carried out in 14 patients who had presented an anaphylactic reaction during general anaesthesia; they were compared with a control group of 14 normal subjects. Histamine release was measured by a fluorimetric method after contact in vitro between patient's basophils and native drug at various concentrations. More than 10 % LHR and a diphasic release curve were considered to be mandatory to certify an anaphylactic origin. The reliability and the specificity of the LHR seemed excellent. The discriminative power between the two groups was statistically significant (p <0.0001). Except for two cases, investigated soon after the accident, in which the total histamine level was too low, LHR appeared reliable and its association with skin tests gave the diagnosis of anaphylaxis in 13 of the 14 cases.