A device (1) for producing an aerosol from vaporizable constituents of tobacco comprises a vaporizing chamber (24) within which the tobacco is placed. A main housing (9) which forms a portion of the vaporizing chamber also forms a combustion chamber (18) within which a gas catalytic combustion element (19) is located for converting fuel gas to heat by catalytic action. A temperature responsive control valve (61) controls the supply of fuel gas to the combustion chamber for maintaining the temperature in the vaporizing chamber A thermal mass (96) secured to a tab portion (95) of the gas catalytic combustion element maintains the temperature of the tab portion at or above the ignition temperature of the gas catalytic combustion element during periods of fuel gas interruption by the control valve. Vaporised constituents of the tobacco are drawn from the vaporizing chamber through an aerosol accommodating tube (37) through a mouthpiece (38). A heat sink member (40) is located in the aerosol accommodating tube for cooling the aerosol and for condensing tar as the aerosol is drawn from the vaporizing chamber.