The tricyclics are antidepressive drugs in widest use today. They are one of the most effective of the psychotropic agents and would be used more often if it was not for the complications. In this article we consider the neurological stimulation that results in undesirable cardio-vascular responses that are the main side-effects of these drugs. First, a brief statement is made about the action of the antidepressive drugs on the synapses for both their therapeutic effects and their side-effects are produced at this level. Despite the many patterns of complications that can occur, it is important to remember that these drugs are still very useful in managing depression and they should be the treatment of choice in depressive syndromes.