The effects of ascorbate and calcium and sodium ascorbate at concentrations of 10(-8)M--10(-2)M on the following functions of human blood lymphocytes were investigated: mitogen-induced DNA synthesis and secreted and intracellular protein synthesis; migration towards a stimulus of endotoxin-activated serum; active E-rosette formation and lymphokine production. The mitogens used were concanavalin A (con A) and phytohaemagglutinin (PHA). No significant effects of ascorbate or its salts on lymphocyte mitogen-induced transformation, intracellular protein synthesis, motility and numbers of active E rosettes were found. However, increased incorporation of radiolabelled amino acids into secreted protein and increased production of leucocyte inhibitory factor (LIF) were observed at calcium and sodium ascorbate concentrations of 10(-6)M--10(-4)M.