The present study illustrates the effects of a standard aqueous extract, used in Cuba under the brand name of VIMANG, from the stem bark of Mangifera indica L. on the production of tumor necrosis factor alpha (TNFalpha) and nitric oxide (NO) in in vivo and in vitro experiments. In vivo was determined by the action of the extract and its purified glucosylxanthone (mangiferin) on TNFalpha in a murine model of endotoxic shock using Balb/c mice pre-treated with lipopolysaccharide (LPS) 0.125 mg kg(-1), i.p. In vitro, M. indica extract and mangiferin were tested on TNFalpha and NO production in activated macrophages (RAW264.7 cell line) and microglia (N9 cell line) stimulated with LPS (10ng ml(-1)) and interferon gamma (IFNgamma, 2U ml(-1)). M. indica extract reduced dose-dependently TNFalpha production in the serum (ED50 = 64.5 mg kg(-1)) and the TNFalpha mRNA expression in the lungs and livers of mice. Mangiferin also inhibited systemic TNFalpha at 20 mg kg(-1). In RAW264.7, the extract inhibited TNFalpha (IC50 = 94.1 microg ml(-1)) and NO (IC50 = 64.4 microg ml(-1)). In microglia the inhibitions of the extract were IC50 = 76.0 microg ml(-1) (TNFalpha) and 84.0 microg ml(-1) (NO). These findings suggest that the anti-inflammatory response observed during treatment with M. indica extract must be related with inhibition of TNFalpha and NO production. Mangiferin, a main component in the extract, is involved in these effects. The TNFalpha and NO inhibitions by M. indica extract and mangiferin on endotoxic shock and microglia are reported here for the first time.