We studied the pharmacologic properties of water soluble extracts of latex dust (LDE) using isolated guinea pig trachea. Dose response relationships between LDE's and contractions of guinea pig tracheal smooth muscle were established. Latex dust was obtained from a plant manufacturing rubber gloves and other rubber products. Two extracts were made by standard antigen preparation methods. The first extract LD1 was prepared from native latex, and the second from a processed form of latex which was relatively free of soluble proteins (LD2). The effects of pre-treatment with mediator blocking agents (pyrilamine, atropine) arachidonic acid metabolite inhibitors (indomethacin, NDGA, acivicin) and an intracellular calcium antagonist (TMB8) were examined and compared to results with similar experiments using cotton bract extracts. The effect of pre-treatment with capsaicin a neuropeptide releasing agent was also assessed. LD1 induced contraction was inhibited by atropine as well as acivicin and NDGA. Similar findings were seen for LD2. Pretreatment with capsaicin did not enhance the effects of LD1 or 2. These studies suggest that water soluble extracts from the latex industry cause airway smooth muscle constriction via mediator release.