This study has investigated the potential for allergic rhinitis (AR) to be induced as a conditioned response, assessed by clinical symptoms and tosyl-l-arginine methyl ester esterase (TE) activity. Twenty seven allergic subjects participated. On conditioning days, Group 1 subjects (n=9) were given a novel drink as a conditioned stimulus (CS) paired with allergen challenge as the unconditioned stimulus (UCS). On the test day, subjects received the novel drink paired with allergen-free PBS. Group 2 subjects (n=9) received novel drink paired with PBS on conditioning days and test day. Group 3 subjects (n=9) consumed tap water paired with allergen on conditioning days and tap water paired with PBS on test day. Analysis of TE activity showed that on test day enzyme activity differed among the groups (χ2 = 6.321, d.f.= 2, p<0.05)(Kruskal-Wallace). TE activity was greater in Group 3 compared with Group 2 (p<0.05) but was not significantly different between Groups 1 and 2. These results suggested that a generalised conditioning effect had occurred in Group 3, that is, conditioning to aspects of the environment other than the novel drink CS. The large heterogeneity of variance contributed by Group 1 on test day (χ2 =31.42, d.f.=2, p < 0.05) (Bartlett 1 ) indicated that the novel drink had a bi-modal effect on the conditioning of AR. The results of this study implicate roles for conditioning, expectation, and the placebo effect in the management of allergic disorders.