tubocurarine: a toxic alkaloid found in certain tropical South American trees that is a powerful relaxant for striated muscles
neuromuscular blocking agent: a substance that interferes with the neural transmission between motor neurons and skeletal muscles
common watercress: perennial Eurasian cress growing chiefly in springs or running water having fleshy pungent leaves used in salads or as a potherb or garnish; introduced in North America and elsewhere