The precise mechanism by which colchicine relieves the pain associated with gout is not known. However, it is believed that major relief involves colchicine's major pharmacological action: binding to tubulin dimers. Colchicine binding prevents curved tubulin from adopting a straight structure, which inhibits assembly.
Colchicum autumnale
                                

Ravelli et al. (2004) Nature 428, 198-202 and www.phc.vcu.edu/Feature/oldfeature/colchicine/colchicine.html