Effect of ramatroban, TM30089, SQ29548 and diclofenac on T helper type 2 (Th2) cytokine production in response to activated mast cell supernatants. Th2 cells were treated with mast cell supernatants (1:2 dilution) in the presence or absence ramatroban, TM30089, SQ29548 or diclofenac as indicated for 5 h. The concentrations of interleukin (IL-4), IL-5 and IL-13 in the incubation media were measured by enzyme immunoassay. Results are expressed as the mean ± standard error of the mean (n = 2–8). P < 0·001 for IL-4 or P < 0·0001 for IL-5 and IL-13 by analysis of variance. P > 0·05 by Newman–Keuls test for unactivated mast cells (UMS) versus mast cells activated with IgE/anti-IgE (AMS) + 1 µM ramatroban/AMS + 1 µM TM30089, AMS + 1 µM ramatroban versus AMS + 1 µM TM30089, AMS versus AMS + 1 µM SQ29548/AMS + 10 µM diclofenac, AMS + 1 µM SQ29548 versus AMS + 10 µM diclofenac, n = 2–8.