I had a very sick friend who vomited all over my guest room carpet and bathroom. I cleaned up as much as I could, but the carpet stain wouldn't go away and odor in the room was unbearable - I was close to having the carpet replaced and calling in a cleaning place that deals with biohazards. After many searches online, I tried one of the suggestions of using Nature's Miracle which is sold in pet stores for pet stains and odors. This stuff saved my guest room - no more odor, no more stain in the carpet (an off-white carpet!). I have since also used it for cat and dog vomit as well and can't believe I went so long without using this. Enzymes in the solution "eat" and break down any organic materials. I first used the spray bottle sizes, then bought the gallon size to refill. You could just buy the gallon size bottle and a generic spray bottle if you know you will use it a lot. You do need to read and follow the instructions exactly, and repeated applications are usually necessary for the vomit I normally have to deal with.