Use of supramolecular carriers of toxic drug molecules can improve the efficiency of medical treatment, especially in the cancer therapy. Binding the drug molecules inside cavity of the host macromolecule protects the drug from degradation and allows its slower release. As a consequence the drug toxicity is reduced and the time between subsequent dosages of the drug is prolonged. Macrocycles of cucurbiturils are able to bind the cationic drugs, such as gemcitabine hydrochloride. Gemcitabine is a potent chemotherapy medication used to treat different kinds of cancer, among others breast, lung and pancreatic cancer. However, its use is limited because of serious side effects caused by its relatively high toxicity for all, also healthy, cells in the stage of division. The carbonyl edges (portals) of cucurbituril cavity create a negatively polarised microenvironment inside which small cationic ligand molecules can be bound and stabilized. The aim of our study was to evaluate the stoichiometry of gemcitabine – cucurbituril complex and to asses thermodynamic parameters describing the phenomenon of binding the drug molecules by a macromolecule of Q7 cucurbituril in aqueous solutions. Thermodynamic binding parameters such as the equilibrium constant of the bound drug and enthalpy and entropy of the formed complex in aqueous solution were evaluated, using the results of the isothermal titration calorimetry (ITC), 1H NMR titration and equilibrium dialysis. Calculated binding parameters confirm the strong interactions between gemcitabine hydrochloride and the Q7 macrocycle with 1:1 stoichiometry.