The objective of the present study was the development and metrological attestation of the method for the determination of concentrations of low-molecular weight (C1—C4) alcohols and acetone in the biological materials, such as urine and blood including partially dehydrated blood. The method is based on the chromatographic analysis of the equilibrium vapour phase with the use of the static headspace autosampler. The calculations were carried out making use of the results obtained with the application of propanol-1 as the internal standard. In order to enhance the reliability of the identification of the analytes in the complex blood matrix, the two-channel configuration was employed that consisted of a single evaporator, passive flow division, two capillary columns of different polarity, and two flame ionization detectors. The proposed technique provided for the first time the unique possibility to perform the quantitative measurement of the internal standard in the starting specimen before the main analysis. The validated procedure for the quantitative determination of the alcohol concentration of blood samples with the reduced water content has been described. The present study made it possible to collect the total amount of relevant statistical data necessary to calculate the metrological characteristics of the method in question. The method was certified based at D.I. Mendeleev All-Russian Research Institute of Metrology under No 754/242-(01.00250)-2016.