 The classic teaching in the anesthetic literature is that depolarizing muscle relaxants do not produce fade upon repetitive stimulation. It means that upon repetitive stimulation, the successive contractions are similar. This is one of the defining features of a depolarizing block and is called a Phase I block. The traditional teaching is that when a depolarizing muscle relaxant is administered in large or repetitive doses, a Phase II block develops. The phase II block has characteristics similar to those of a nondepolarizing muscle relaxant ie fade on repetitive or TOF stimulation. De Jong and Freund first proposed that this differentiation between deplolarizing and nondepolarizing block based upon fade may not be as clear cut. These investigators demonstrated that succinylcholine caused fade upon repetitive stimulation right from the outset of the neuromuscular block. Other investigators have also demonstrated that succinylcholine causes fade from the initiation of the neuromuscular block. If it can be conclusively demonstrated that succinylcholine causes fade, then fade would be less useful in differentiating a depolarizing from a nondepolarizing block. We have previously investigated and defined the fade caused by nondepolarizing muscle relaxants. Using the experience we have gained in studying fade with nondepolarizing muscle relaxants, we would like to now define the characteristics of fade if any caused by succinylcholine. 