With the advent of novel monocomponent venoactive drugs containing the flavonoid diosmin, the need has arisen to answer the question of therapeutic equivalence of the widely used micronized purified flavonoid fraction (MPFF) contained in Detralex and of the currently introduced monocomponent venoactive drugs. Experimental work provides evidence that each of the two dominant components, i.e. diosmin and hesperidin, has its specific and distinctive pharmacodynamic effect. There is also evidence of a mutual synergistic effect, e.g. in antiexudative action. Clinical studies have been carried out with MPFF for the most part, and effect has clearly been established in this particular form. Conversely, the results of studies documenting the effect of diosmin alone have been conflicting. Mutual comparisons failed to confirm equivalence of MPFF and monocomponent diosmin in any of the studies. This fact is clearly reflected in the relevant guidelines where the use of MPFF in chronic venous disease is recommended unequivocally (level of evidence 1 and strength of evidence B) while, in the case of monocomponent diosmin, it is stated that treatment can be considered (2C). It can be concluded that both experimental and clinical studies document that only a complex of biologically active flavonoids - a micronized purified flavonoid fraction - has evidence of effect and is recommended by relevant guidelines.