The supposed immunostimulatory actions of MSC, a new fermented wheat germ extract standardized to its benzoquinone composition (trade name: AVEMAR) were studied examining blastic transformation of peripheral blood lymphocytes of mice treated with MSC. It was found that MSC significantly increased the degree of blastic transformation caused by Concanavalin A. Using the B10LP to C57Bl skin graft system, MSC (0.03 and 3.0 g kg-1 applied orally) acted in favour of restoring the immune function. On the other hand, 2,6-dimethoxy-p-benzoquinone (DMBQ), applied in equivalent doses (0.012 and 1.2 mg kg-l), did not shorten the rejection time of skin grafts. The immune restoring effect, as well as the blastic transformation enhancing potential of MSC may be exploited in various cases of decreased immune response.