A Roux culture bottle, or simply Roux bottle, is a type of laboratory glassware used in biology and related sciences to grow microorganisms or tissue cells.^{[1]: 5 [2]: 1886} It consists of a bottle of transparent glass^[3] or plastic^[4] with two closely spaced flat, rectangular, parallel faces and a short neck; of such a design that the bottle can be laid down sideways, on one of those two faces, even when unstoppered and partially filled with a culture medium. This goal is achieved by having the neck narrowed,^[3] offset,^[5] partially blocked,^[6][7] or canted (tilted).^[8][9] The item is also generically called cell culture bottle^[4] or tissue culture (TC) bottle,^[8] and flask may be used instead of "bottle".^[3]

A Roux bottle provides a large surface for the cells or microorganisms to grow, whether on the top of,^[10] floating in,^[11] or at the bottom of the medium.^[12] The flat upper face then allows inspection of the culture and even illumination for photosynthetic organisms.^[11] Organisms growing at the bottom of the medium can also be inspected from below, with an inverted microscope.^[13]

The bottle is typically closed with a plug or cap that prevents contamination of the culture by spores from the outside, while still allowing exchange of gases generated or consumed by the organisms inside.^[12]

The bottle's invention has been attributed to French physician and Pasteur's collaborator Pierre Roux (1853-1933).^[14][15]