Purpose: The effect of an oral trans-resveratrol-based supplement (Longevinex((R))) on choroidal thickness, measured using optical coherence tomography (OCT) enhanced depth imaging, was investigated in a prospective study.Materials and Methods: 34 young, healthy participants were randomly divided into two age- and gender-matched groups. They were then assigned in a randomized fashion to treat with either a trans-resveratrol-based group (Longevinex((R)), Las Vegas) or placebo. All participants underwent ocular imaging with spectral domain (SD)-OCT (Spectralis; Heidelberg Engineering, Heidelberg) at the baseline and then again 1 h following treatment. The choroidal thickness was measured in a masked fashion at the fovea and at four additional points, located at 500 m and 1000 m nasal to the fovea and 500 m and 1000 m temporal to the fovea.Results: In the resveratrol group, the foveal choroidal thickness at the baseline was 267.73 84.19 m (mean +/- SD); it increased to 284.57 +/- 92.39 m 1 h after drug treatment (p = 0.033). The mean choroidal thickness was also significantly increased at each of the four extrafoveal points (all p < 0.05). In the control group, the mean baseline choroidal thickness at the fovea was 269.73 +/- 71.40 m (mean +/- SD) and it was 268.43 +/- 70.15 m (mean +/- SD) 1 h after the placebo was administered (p = 0.183); there were also no significant differences in choroidal thickness at the four additional points (all p > 0.05)Conclusion: A significant increase in choroidal thickness following oral administration of a trans-resveratrol-based supplement was observed. There was no change in choroidal thickness in the placebo-treated control group. We speculate that the increased choroidal thickness is the result of choroidal vessel vasodilation.