Everybody comes across it sometimes, having to remove vomit stains from clothing. Some options are listed here.

At first as much as possible needs to be removed by washing it down under the tap. This way no more vomit can get in to the cothing. Make a mixture of water, a dash of vinegar and detergent. Dab the stain carefully and rinse with luke warm water. Repeat this method until the stain is removed. Afterwards it can be washed in the machine.

Alternative method would be to soak the clothing in water with a dash of vinegar and washing it in the machine afterwards.