Summary—The effects of nicotinamide on hepatocyte viability and secretion of albumin and α1‐acid glycoprotein were studied in the absence or presence of dexamethasone and/or recombinant human interleukin‐6 either after cell attachment (2 h) or after 24, 48, and 72 h of culture. The evolution of hepatocyte survival during the culture was appreciated by measurement of total DNA content. The secretion of albumin and α1‐acid glycoprotein was measured after a 4‐h period following cell attachment or after 24, 48 and 72 h of culture. The important decrease of DNA content, mRNA levels and secretion of albumin and α1‐acid glycoprotein in control cultures after 2–3 days was not prevented by the addition of nicotinamide. In contrast, dexamethasone alone or with recombinant human interleukin‐6 improved DNA content and albumin secretion with no additional effect of nicotinamide. The secretion of α1‐acid glycoprotein was largely induced by dexamethasone alone or dexamethasone and recombinant human interleukin‐6. The increase of α1‐acid glycoprotein secretion was not modified by the addition of nicotinamide and averaged respectively 27‐ and 60‐fold for dexamethasone alone and dexamethasone and recombinant human interleukin‐6 after 48 h. These observations suggested that nicotinamide, at least in the conditions tested here, is unable to prevent alterations of hepatocyte viability and gene ex