Nowadays, cosmetic fillers are widely used and the reports of complications are rising. Therefore, the possibility to detect and identify noninvasively new fillers can provide a potent tool for managing complications. The objective of this study was to assess the ultrasound morphology of polycaprolactone. First, polycaprolactone was injected into porcine skin and this sonographic morphology was prospectively compared with the one observed in patients injected with this filler. On sonography, polycaprolactone shows as hypoechoic deposits that present multiple bright hyperechoic spots with mini-comet-tail artifact. This morphology differs from the ultrasound appearance of other common fillers.