Histamine plays fundamental roles in numerous immune reactions. In addition to its well-characterized effects in the acute inflammatory and allergic responses, histamine also influences the expression and actions of several cytokines. The interaction between histamine and the cytokines is bidirectional, since some cytokines were found to modulate the production and release of histamine as well. Because several pharmacological agents that modulate the actions of histamine (e.g. antihistamines) are widely used in the treatment of various human diseases (allergy, peptic ulcer etc.), this complex interaction could have general medical relevance too, but the current situation appears to be rather controversial and further studies are needed to elucidate these sophisticated interactions more precisely.