An aqueous foamable aerosol composition maintained under pressure greater than atmospheric pressure comprises a foamable material, at least 1%, and preferably from 5% to 20%, based on the weight of the foamable material, of disintegrated cellulose crystallite aggregates having a level-off D.P. and prepared as described in Specification 874,945, or topochemical derivatives thereof, at least 1% by weight of the disintegrated cellulose crystallite aggregates or derivatives having a particle size less than one micron, and a material that is a gas at atmospheric pressure.  The topochemical derivatives of cellulose crystallite aggregates have a degree of substitution of at least 0.01 and are disclosed in Specification 976,335. The foamable material may be a proteinaceous substance which may comprise about 3 to 15%, suitably 5 to 11% of the product.  It may be milk or a milk product, cream or a cream product, sodium caseinate, lactalbumin, lactoglobulin, the proteose-peptone fraction of skimmilk, gluten, soybean flour, yeast, gelatin, egg white, egg yolk, or albumen.  The foamable material may be a surface-active compound such as a monoester or diester of a fatty acid and a polyhydric alcohol, or a soap.  The compound may comprise 0.05 to 10% by weight of the composition.  A long list of foamable materials is given.  Those used in examples are mixtures of:  (1) Milk-solids-not-fat, sucrose, propylene glycol, and glyceryl monostearate. (2) Sodium proteinate prepared from soya beans, sucrose, monoglycerides, carboxymethyl cellulose and coconut fat. (3) Sugar, salt, mustard, cottonseed oil, egg yolk, vinegar, lemon juice, glyceryl monostearate and carboxymethyl cellulose.  (4) Oleic acid, and triethanolamine. (5) Sodium metaphosphate, and sodium lauryl sulphate.  The proportion of cellulose crystallite aggregates in the compositions of the examples ranged from 2 to 10% and the proportion of water from 58 to over 90% by weight. The mixture of cellulose aggregates and foamable material may be packaged with the propellant by cooling the mixture and introducing it into a conventional aerosol dispenser charged under pressure with a conventional propellant which may be nitrogen, nitrous oxide, carbon dioxide, dichlorodifluoromethane, or a mixture of perfluorocyclobutane with any of the foregoing. The compositions may be edible toppings for cakes, salad dressings, shaving creams, or dentifrice creams.  The derivatives of the cellulose crystallite aggregates may be carboxymethyl, hydroxypropyl or acetate derivatives and may have a degree of substitution (D.S.) of up to about 0.4. They are insoluble in water and/or organic solvents and impart the same properties to the foamed compositions as do the cellulose crystallite aggregates.ALSO:An aqueous foamable aerosol composition maintained under pressure greater than atmospheric pressure comprises a foamable material, at least 1%, and preferably from 5% to 20%, based on the weight of the foamable material, of disintegrated cellulose crystallite aggregates having a level-off D.P. and prepared as described in Specification 874,945, or topochemical derivatives thereof, at least 1% by weight of the disintegrated cellulose crystallite aggregates or derivatives having a particle size less than one micron, and a material that is a gas at atmospheric pressure.  The topochemical derivatives of cellulose crystallite aggregates have a degree of substitution of at least 0.01 and are disclosed in Specification 976,335.  The foamable material may be a proteinaceous substance which may comprise about 3 to 15%, suitably 5 to 11% of the product.  It may be milk or a milk product, cream or a cream product, sodium caseinate, lactalbumin, lactoglobulin, the proteosepeptone fraction of skim-milk, gluten, soybean flour, yeast, gelatin, egg white, egg yolk, or albumen. The foamable material may be a surface-active compound such as a monoester or diester of a fatty acid and a polyhydric alcohol, or a soap.  The compound may comprise 0.05 to 10% by weight of the composition.  A long list of foamable materials is given.  Those used in examples are mixtures of: (1) Milk-solids-not-fat, sucrose, propylene glycol, and glyceryl monostearate.  (2) Sodium proteinate prepared from soya beans, sucrose, monoglycerides, carboxymethyl cellulose and coconut fat. (3) Sugar, salt, mustard, cotton seed oil, egg yolk, vinegar, lemon juice, glyceryl monostearate and carboxymethyl cellulose.  (4) Oleic acid, and triethanolamine.  (5) Sodium metaphosphate, and sodium lauryl sulphate. The proportion of cellulose crystallite aggregates in the compositions of the examples ranges from 2 to 10% and the proportion of water from 58 to over 90% by weight.  The mixture of cellulose aggregates and foamable material may be packaged with the propellant by cooling the mixture and introducing it into a conventional aerosol dispenser charged under pressure with a conventional propellant which may be nitrogen, nitrous oxide, carbon dioxide, dichlorodifluoromethane, or a mixture of perfluorocyclobutane with any of the foregoing.  The compositions may be edible toppings for cakes, salad dressings, shaving creams, or dentifrice creams. The derivatives of the cellulose crystallite aggregates may be carboxymethyl, hydroxypropyl or acetate derivatives and may have a degree of substitution (D.S.) of up to about 0.4. They are insoluble in water and/or organic solvents and impart the same properties to the foamed compositions as do the cellulose crystallite aggregates.