Partly because of his poor health, he tended not to practise as a physician, his interests lying in the deeper problems of medical and physiological science. During the last two years of Honoré Mirabeau's life, Cabanis was intimately connected with him; Cabanis wrote the four papers on public education which were found among Mirabeau's papers at his death (and Cabanis edited them soon afterwards in 1791). During the illness which terminated his life Mirabeau trusted entirely to Cabanis' professional skills. Of the death of Mirabeau, Cabanis drew up a detailed narrative, intended as a justification of his treatment of the case. He was enthusiastic about the French Revolution and became a member of the Council of Five Hundred and then of the Senate, and the dissolution of the Directory was the result of a motion which he made to that effect. His political career was brief. Hostile to the policy of Napoleon Bonaparte, he rejected every offer of a place under his government. He died at Meulan.
