Is it the food you most recently ate?
Most vomiting starts out looking like whatever it was you ate last. If you just vomit a few times and it consists of food, it could be a stomach virus, food poisoning or something completely different -- like pregnancy.
Is it bright green?
Vomit that is dark green is typically bile. For children, this can signal a serious illness that requires immediate medical attention. It can also occur when a person has vomited so much that there is no food or liquid left in their stomach. In this case it may be an indication of dehydration.
Is it bright red?
If you are vomiting bright red, it could be blood. Other causes of red vomit can be recently eating or drinking something red or a recent nosebleed. If you know you have not recently had anything red to eat or drink, and have not has a nosebleed, then the presence of bright red vomit indicates a medical emergency.
Is it black and look similar to coffee grounds?
Black vomit that looks like coffee grounds may also be blood. If it is not fresh blood, it will often turn very dark and look black when you vomit. Although there may not be active internal bleeding, vomit that looks like coffee grounds is still considered a medical emergency.