The demonstration that several agents with presumed differing mechanisms of action each provide partial effectiveness in the treatment of relapsing-remitting multiple sclerosis (MS) has significantly changed the approach to MS clinical trial research. A number of recently published trials have provided support to these pivotal reports that the short-term course of MS may be favorably influenced by one of a number of treatments. More phase III trials with these and other agents will be completed shortly. Several promising agents have recently been found to be either of no benefit or too toxic for widespread use, whereas several unconfirmed "positive" trials have contributed to a sense of guarded optimism. Important revisions to conventional MS trial methodology are evolving. Additional revisions are needed, however, to expedite the identification of agents that are likely to merit further study and to remove useless or toxic agents from the growing list of potential candidate treatments. These research trends and suggestions for future methodological revisions in the approach to this aspect of MS clinical research are reviewed here.