The solid, form-stable gel for hair treatment contains an aqueous or aqueous-alcoholic base; from 0.5 to less than 2 percent by weight of a carrageenan or a mixture of carrageenans and at least one carrageenan-amount-reducing additive selected from the group consisting of hair fixing polymers, amphiphilic associative thickeners, monoalcohols with 1 to 5 carbon atoms and polyalcohols with 2 to 5 carbon atoms. The carrageenan or mixture of carrageenans and the at least one additive are contained in the gel in respective amounts so that the gel is solid and form-stable, i.e. has a resistance of at least 0.15 N to a compressive force applied at 2000 and 65% relative humidity by means of an 8 mm diameter cylindrical piston that is depressed at a rate of 0.5 mm/s until a compression depth of 1 mm is reached after which the piston is removed at a rate of 0.5 mm/s.