Cytokines are essential mediators of cell-to-cell communication in many physiological and pathophysiological processes. During the last few years a lot of data has accumulated suggesting that some of them may be involved in the pathomechanism of multiple sclerosis (MS). One of the most extensively studied is a cytotoxic cytokine--tumour necrosis factor (THF) which has demyelinating activity in vitro and in vivo. Similar in structure and functions is another cytotoxic cytokine-lymphotoxin (LT). In the article recent information about studies of TNF and LT in MS were reviewed.