A stable dye solution which has a high concentration of dye and which is miscible with water in any proportion, is described which dye solution contains(a) 20 to 40 percent by weight of at least one azo, nitro or anthraquinone dye containing acid groups, in particular sulphonic acid groups,(b) 20 to 80 percent by weight of N-cyclohexylpyrrolidone,(c) optionally 0.1 to 20 percent by weight of water, and(d) optionally 0.1 to 50 percent by weight of a glycol or glycol ether or of a mixture thereof,As well as, optionally, further additives; the said dye solution is suitable in particular for the continuous dyeing of carpets.