The patent literature pertaining to agents for the treatment of migraine headache and related disorders has been reviewed for the period of July 1, 1995 to December 31, 1996. Included are patents on serotonergic agents, such as 5-hydroxytryptamine 1D (5-HT1D) receptor subtype agonists and 5-HT2 and 5-HT3 antagonists. Also covered are patents describing chemical entities that may be effective in migraine therapy based on their pharmacological actions as adrenergic agents, tachykinin receptor antagonists or inhibitors of nitric oxide synthetase (NOS). Selected references from the recent scientific literature have also been cited.Exp. Opin. Ther. Patents (1997) 7(5):511-521 2.1 5-HT 1 receptor subtype agonists Table 1 summarises the structural features and the types of supporting biological data for a variety of tryptamine and homotryptamine derivatives, which like sumatriptan, function as agonists at 5-HT1D or related serotonin receptor subtypes. These compounds bear a diversity of substituents at the indole 5-position (substituent X) and include chemotypes in which the basic nitrogen and/or its appending sidechain are incorporated into a ring. The in vitro biological data includes receptor binding affinities for 5-HT 1D and other 5-HT1 subtypes, as well as contractile activity upon vascular preparations, and was obtained using either recombinant human receptors or the appropriate brain or vascular tissues from various other species 511 511 1997 © Ashley Publicat ions Lt d.