Murine helper T cells can be divided into at least two groups, Th1 and Th2, based on the patterns of lymphokine secretion after antigenic or mitogenic stimulation. Recently, a similar subdivision was proposed in the human situation. Interestingly, the different patterns of lymphokine production correlate with different effector functions of the Th subpopulations. Th1 cells appear to dominate delayed type hypersensitivity reactions. Conversely, Th2 cells dominate the immune response to allergens and probably play an important role in allergic disorders. One of the clinical manifestations in which Th2 cells appear to dominate the immune response is allergic asthma. The mainstay of therapy in asthmatic persons is formed by glucocorticoid and beta-adrenoceptor agonist treatment. A differential pharmacological modulation of the lymphokine production by Th1 and Th2 cells can be of therapeutic relevance in allergic diseases in which an inappropriate balance between Th1 and Th2 cells exists. Such a differential modulation may underlie the beneficial usage of glucocorticoids and beta-adrenoceptor agonists in the treatment of asthma. The present report summarizes the effects of glucocorticoids and cAMP modulating agents on the activation and lymphokine production of T lymphocytes and Th subsets. Additionally, the effect of other steroid hormones is evaluated.