The clinical indications and potential uses of botulinum toxin A (BtA) have steadily increased since it first became available for clinical use in the late 1980s. A pattern has emerged of anecdotal reports of possible benefit in a new indication, followed by multiple small uncontrolled or open studies, with the eventual publication of controlled and blinded trials. This process has been fastest in easily defined clinical situations such as focal dystonias - blepharospasm is a good example - and slowest in the more complex world of rehabilitation. For some indications, uncritical initial enthusiasm has created an atmosphere inhibiting adequate controlled trials.