Horses are unable to throw up, that's why colic can be deadly to them, they can't get the contents out of their stomach.

I'm pretty sure they dont. Do they even throw up?

Raised horses for years and colic is the worst..I have walked many a mile leading a colicing horse so they wouldnt lay down..Once down..almost imposible to get htem up again...So I walked them till vet arrived and gave them medicine..even then I lost one..

The gastroesophageal sphincter (where the esophagus empties into the stomach) acts as a one-way valve that only allows food and water to enter the stomach from the esophagus. Horses, therefore, are incapable of vomiting, which, as others have mentioned, is problematic. Colic is a general term for any pain originating from the abdomen. In most cases this pain is related to the gastrointestinal tract with many different possible causes. In relation to this question, there are two primary causes of pain originating from the stomach: duodenitis-proximal jejunitis (aka anterior enteritis) and small intestinal obstruction. Both of these prevent ingesta from progressing through the intestines. Unfortunately, the horse constantly secretes gastric and intestinal fluids (acid, bile, etc.) and because the horse cannot vomit, the stomach fills up with fluid and becomes very painful. Veterinarians can relieve some of this pain by passing a nasogastric tube into the stomach (DO NOT try this on your own) and remove the accumulated fluid. This is also a useful tool for helping to diagnose the cause of the colic. Fortunately, most cases of colic resolve on their own or respond quickly to treatment, but occasionally some horses will require hospitalization and/or surgery and may even die from the cause of their colic. With regards to the comment about cattle vomiting. Strictly speaking, cattle (and other ruminants) cannot vomit as, by definition, vomiting is a forceful expulsion of gastric contents. This is due to the complex four chambered stomach of ruminants. However, ruminants are capable of eructation (essentially, burping) and regurgitation. Regurgitation in the ruminant is not the same as vomiting as it is under voluntary control and is not a forceful expulsion of ruminal content. Rather it is the controlled movement of a small amount of corse material (cud) that is pushed back into the esophagus, "unswallowed", then rechewed and reswallowed. If eructation (and regurgitation) are disrupted (again, numerous possible causes), ruminants are unable to expel accumulating gas which causes rumen distention and pain (referred to as 'bloat'). I apologize if this explanation seems incomplete, I was trying to expand on previous answers but still keep it rather basic.

Horses cannot throw up. Horses colic instead.

Horses colic, it s phiically impossible for them to thow up

Horses are unable to throw up and as such it is very wise to avoid anything that may set off stomach upset and pain. (defined in a horse as colic) Signs of colic include sweating, yawning, pawing the ground, unusual gut sounds, biting at stomach and flank area, stretching, rolling. Not all signs are present and others may be seem. Causes of colic can include an overload of fresh pasture or grain. All feed and pasture changes should be made gradually.