Curare, containing the alkaloid curarine, is a South American arrow-poison. It is probably obtained from a species of Strych-nos, the genus to which the strychnine-yielding plants belong. Its essential action is to paralyze the motor end-plates in striped muscles, and for this purpose it is largely used in physiologic and pharmacologic laboratories. It has been used in certain convulsive or spasmodic conditions of striped muscle, but its dosage is very uncertain, and its tendency to paralyze the respiratory muscles is marked, hence it is too dangerous.