Background: Brain is the most sensitive organ, whereas brainstem is the most important part of CNS. It connects brain and spinal cord. However, a myriad of drugs and chemicals affects CNS with severe resultant effects on brainstem.
Method: In view of this, literatures were assessed for information on the most sensitive part of brain, drugs and chemicals that act on the brainstem and clinical benefit and risk assessment of such drugs and chemicals.
Results: Findings have shown that brainstem regulate heartbeat, respiration and because it connects brain and spinal cord, all the drugs that act on spinal cord may overall affect the systems controlled by the spinal cord and brain. The message is sent and received by temporal lobe, occipital lobe, frontal lobe, parietal lobe and cerebellum. Therefore, the receptors in all the different parts of brain have chemical compounds with structures that match the functional groups of the brainstem acting drugs. Nitrogen, oxygen, Sulphur, hydrogen and hydroxyl group may be the parts of functional group or functional group of both the brainstem acting drugs and their receptors.