Ion transport enzymes may play an important role in T cell activation. This study investigates the role of turmeric and its individual components, turmerin-and curcumin- on Ca2+ and Na/K+ adenosine triphosphatases (ATPase) in the course of T cell activation. Concanavalin A ( Con A) stimulated human blood mononuclear T cell proliferation paradigm was investigated for 3, 5 and 7 day periods with different concentrations of turmeric, curcumin and turmerin. Con A-stimulated cells treated with turmeric (250, 50, 5 mug/ml) for 3 and 5 days inhibited ATPase levels when compared to base levels obtained by cells in media alone. At day 7, there was a 3-fold increase for Ca2+ ATPase levels and a 2-fold increase for Na/K+ ATPase. Curcumin (250, 50, 5 mug/ml) showed the same pattern for ATPase activity as turmeric at 3 and 5 days with a 2-fold increase at day 7. Turmerin (2500, 1250, 250, 25 ng/ml) for Na/K+ ATPase activity showed an increase at day 3, a decrease on day 5, and a 2-fold increase on day 7. Ca2+ ATPase activity in the presence of turmerin showed an increase in ATPase levels at day 3 (except at 2500 ng/ml where it decreased) and a decrease in day 5 (except at 25 ng/ml where it increased). Turmeric and curcumin generally inhibited Ca2+ ATPase and Na/K+ ATPases in early (day 3) and intermediate ( day 5) stages of mitogen stimulation. However, the effect after 7 days incubation for turmeric, curcumin and turmerin showed a marked increase up to three fold.