Purgatives are substances inducing defaecation and along with analgesics they are drugs most frequently used by patients without consulting their physician. The classification of purgatives is not simple as the mechanism of action is not quite clear in many purgatives and many probably act by more than one mechanism. The majority of purgatives with the exception of docusates and oligosaccharides act similarly. A systematic analysis of purgatives did not confirm unequivocally a better effectiveness in favour of one of the used purgatives. Purgatives have however in addition of the mentioned effect on defaecation also undesirable effects to which attention is drawn in the submitted article and the authors discuss in more detail individual purgatives also with regard to the mechanism of their action and their chemical composition.

        Key words: purgatives – effect – composition – undesirable effects – toxicity