Atorvastatin inhibits T cell proliferation and interleukin (IL)-2 production in a dose-dependent manner. Splenocytes from C57BL/6 mice were cultured in the presence of either (a) anti-CD3 + anti-CD28 antibodies (b) staphylococcal enterotoxin B (SEB) or (c) Lactobacillus casei cell wall extract (LCWE) and atorvastatin for 72 h, with [3H]-thymidine added for the last 16 h of incubation. Cells were harvested and radioactivity measured in a liquid scintillation counter. Data representative of at least three independent experiments. ***P < 0·001, **P < 0·01 versus control (no atorvastatin). (d) Splenocytes from C57BL/6 mice were cultured in the presence of SEB and various concentrations of atorvastatin for 48 h, supernatant collected and concentration of IL-2 determined by enzyme-linked immunosorbent assay. Data represent at least three independent experiments. ***P < 0·001, **P < 0·01 versus control (no atorvastatin), by analysis of variance.