The aim is to shed light on new information on the mechanisms of IBS and ID under conditions of comorbidity and the possibility of improving their comprehensive treatment with the use of multicomponent herbal medicines.Materials and methods. A scientific research was done in modern printed publications and scientific databases, the State Register of Medicines of Ukraine, the results of own research with the use of multicomponent herbal medicines at IBS and ID are represented.Results. Current scientific data indicate the pathogenic role of intestinal microflora in the occurrence of the most common diseases of internal organs and the mutual adverse effects of other digestive and extradigestive comorbid diseases on the manifestations, course and results of treatment of IBS and ID in age aspect. With increasing age, quantitatively, intersystemically and clinically more pronounced comorbidity deepens, complicates the pathogenetic relationship between IBS and ID and requires additions to the generally accepted principles of treatment of IBS and ID, which would take into account new pathogenetic realities within the digestive system, vascular and immunological disorders. In this aspect, the authors, according to the analysis of the literature on phytotherapy and the pharmaceutical market of Ukraine, tested on a significant contingent of patients (680 people) with IBS, ID and various comorbid processes four multicomponent phytomedicines with different mechanisms of differentiated action in accordance with identified clinical and age-related disorders. Complex treatment of patients was resulted in acceleration of regression of clinical manifestations of diseases, reduction of frequency of relapses, prolongation of remissions’ duration are achieved.Conclusions. It is advisable to take into account the pathogenetic features of the formation of IBS and ID in young, mature, elderly and senile people, taking into account age-related comorbid processes in clinical, vascular-metabolic, immunological, prognostic aspects. In order to increase the effectiveness of treatment according to the established new pathogenetic relationships of diseases in addition to existing standards of treatment to prescribe multicomponent herbal medicines with different systemic mechanisms of action.