In his Reply to Porphyry (De mysteriis) I.11 Iamblichus compares the benefits of watching and listening to ecstatic ritual with the effects of tragedy and comedy which stabilize and purify the emotions, making them more moderate (metriōtera). Iamblichus here appears not only to accept the notion of catharsis found in Aristotle’s Poetics and Politics but also to associate this with metriopatheia and so with civic virtue (politikē aretē). Elsewhere, in Reply to Porphyry III.9 and On the Pythagorean Life chs.15 (64) and 25, Iamblichus discusses the role of music in therapy of the emotions. I shall examine the relationship between these passages and Reply to Porphyry I.11 and will argue that for Iamblichus emotional therapy through music is associated with the condition of the soul which later Neoplatonists labelled as ‘natural’ or ‘habituated’ virtue (physikē or ēthikē aretē) rather than with civic virtue.