SUMMARY1. Focal ischaemia was produced experimentally inMacaca radiatamonkeys by occlusion of middle cerebral artery (MCA). There was a lowering of the dopamine (DA) content of basal ganglia after 4 and 12 h of occlusion.2. DA content was restored to normal in basal ganglia after restoration of blood flow. With the progress of time the DA content was increased above that of sham controls. Changes were also observed in the non‐occluded left basal ganglia.3. The homovanillic acid (HVA) content was decreased significantly at 12 h after occlusion. After the onset of reflow, the HVA content of the right basal ganglia was higher than that of sham controls.4. The 3, 4 dihydroxyphenylacetic acid (DOPAC) content of right basal ganglia was significantly decreased after 12 h occlusion. Reflow restored the level of DOPAC to normal within 1 h after removal of clip.5. Discrete changes were also observed in the left basal ganglia at some of the time interval