BACKGROUND Stroke is the third common cause of mortality and the most common cause of morbidity in adults. MLC601 (NeuroAiD™) is a treatment indicated for post stroke recovery. An increase of impaired cerebral blood flow may be an important parameter for recovery processes. The aim of this study was to investigate the effect of MLC601 on cerebral blood flow velocity as an indirect evidence of cerebral blood flow increase in post stroke subjects. METHODS This is a double-blinded, placebo controlled, randomized study of 80 subjects included within a week of stroke onset. All subjects were given either MLC601 or placebo, 4 capsules, 3 times a day for 3 months. Cerebral blood flow within the middle cerebral artery, with blood flow velocity measured by transcranial Doppler (TCD), and Barthel index was assessed at baseline and at 3 months. RESULTS The mean change in cerebral blood flow velocity in the MLC601 treatment group (15.9) was significantly increased (p=0.009) compared to the placebo group (9.6). Subjects in the treatment group also showed a significant difference in the mean rank of modified ranking scale (p<0.001) and mean change of the Barthel Index: 36 vs. 29 in the placebo group (p<0.001). CONCLUSION This is the first study suggesting that treatment with MLC601 may increase cerebral blood flow in stroke subjects. This may be mediated by an effect on stimulating microcirculation, an important process contributing to neuroplasticity in the central nervous system. This effect on cerebral blood flow may be associated with improvement in measures of functional recovery.