Objective. To investigate the effectiveness of infusion chemotherapy in patients with pulmonary tuberculosis (TB) with treatment failure and malabsorption syndrome.
 Materials and methods. We observed 52 patients with newly diagnosed pulmonary TB with treatment failure, who were diagnosed with malabsorption syndrome. Patients were divided into two groups: 1st group (main) included 24 patients who received rifampicin and ethambutol intravenously, pyrazinamide and isoniazid orally; 2nd group (control) – 28 patients who received standard therapy orally. The severity of malabsorption syndrome was determined by a violation of intestinal penetration. Intestinal penetration was determined by the concentration of lactulose and mannitol (lactulose-mannitol test) in urine. The concentration of rifampicin, isoniazid, ethambutol in the serum was determined by liquid chromatography on a chromatograph Perkin Elmer (USA).
 Results and discussion. The examination revealed a violation of the rate of intestinal penetration in all studied patients, compared with healthy donors. The concentration of anti-TB drugs in the serum was significantly lower than the therapeutic average in group 2 compared with group 1 (p<0,05). In patients of group 1 after the intensive phase of treatment, the disappearance of clinical symptoms of the disease was observed in 22 (91.3±5.8 %) and 17 (60.7±6.3 %) patients (p<0.05), cessation of mycobacterial excretion – in 20 (83.3±4.3 %) and 14 (50.4±4.6 %) (p<0.05), resorption of infiltrative changes and healing of destruction cavities in the lungs – in 12 (50.2±5.3 %) and 10 (35.7±4.7 %) (p<0.05) compared with group 2.
 Conclusions. In patients with malabsorption syndrome with ineffective treatment and low intestinal penetration, which leads to reduced serum concentrations of anti-TB drugs in the intensive phase of treatment, it is advisable to increase the effectiveness of intravenous rifampicin and ethambutol.