A method of stabilizing a core sample is described, and an agent for use in the stabilising method. The method involves injecting a foam around a core sample in a cylindrical liner. The foam comprises mixture of a first pressurized polymerisable-based fluid and a second pressurized fluid, which are simultaneously injected as a foam into an annulus between the core sample and liner. The foam preserves the sample and cushions it for transportation. The foam can include a dye or colorant to distinguish the foam from other materials in the core sample.