In Περὶ Φύϲεωϲ, Book XXXIV, col. 20-21, Epicurus twice uses the term φλεβοπαλία («pulse», «beating of the pulse») in connection with mental images which appear in dreams. Although Epicurus’ text, in its present state, does not make perfectly clear the nature of this connection, it probably concerns internal reactions to images arising from the surrounding environment. Before Epicurus, φλεβοπαλία is attested only in Democritus, and this raises the question of a possible allusion. This article supports the hypothesis that Epicurus refers to Democritus and that, in this instance, his attitude is not polemical. Rather, he seems to re-appropriate a Democritean term for his own purposes, which apparently consist of giving a physiological and naturalistic explanation of some dream images in order to dismiss false and superstitious beliefs about their sources and nature. Furthermore, regarding the Democritean background, it is argued that pulse and blood have an important part in Democritus’ own theory of perception, as several testimonies reveal, in particular Theophrastus’ De sensibus.