Block copolymer pharmaceutical compositions containing 3,3′-diindolylmethane (DIM). The pharmaceutical composition for peroral administration comprises 3,3′-diindolylmethane as an active component and a target additive, the target additive being a block copolymer of oxyethylene and oxypropylene, in which the content of the hydrophobic oxypropylene block is less than 50 mass % and the molecular mass of the hydrophilic oxyethylene block is equal to 2,250 Da or more, at a ratio of the active component to the selected block copolymer varying between 1:2 and 1:10. The composition improves absorption of the active compound by the bloodstream upon peroral delivery.