The utility model relates to a disposable vomit bag, which is provided with a single mouth plastic bag made of degradable plastic. The mouth of the plastic bag is covered with a set of shell, the shell is provided with an upper port and a lower port, the diameter of the upper port is greater than the diameter of the lower port, and the upper port and the lower port are connected; The upper end of the casing is extended outwards, and the plastic bag mouth passes through the lower end of the casing and extends out from the upper end of the outer part of the extension of the port on the shell sleeve; A bayonet is arranged on the lower port of the shell sleeve; And the plastic bag is provided with a puffed substance that can naturally absorb water. The disposable vomit bag has a simple structure. After use, the bag body can be buckled into the bayonet to effectively prevent the leakage of vomit and its odor. Moreover, the disposable vomit bag can also be used for the placement of other waste items.