Defining Colic (Book Excerpt)

Editor's Note: This is an excerpt from Understanding Equine Colic by Bradford G. Bentz, VMD, MS. It is available from

It is important to define the word colic in order to understand its meaning, as it pertains to the horse.  A common misconception is that colic is a specific diagnosis associated with a well-defined cause. However, colic is, in reality, merely a clinical sign and not a diagnosis.  The term colic actually means, in the broadest sense, abdominal pain.  Abdominal pain is relatively common, even in people. We tend to refer to our abdominal pain as "stomach aches." Most of the time when people get "stomach aches," we have no idea what has specifically taken place to cause the pain. We also realize that we are likely to recover from the discomfort without medical (or surgical) intervention.  Therefore, we often never discover the cause of our "stomach aches." In horses, numerous conditions, both specific and non-specific, may also lead to abdominal pain, yet most of these conditions go undiagnosed because of the self-limiting nature of most of the causes of colic. Colic is the manifestation of the cause of abdominal pain and not a specific diagnosis of its cause. 

Although animals and humans experience abdominal pain (colic), horses, for many reasons, seem especially prone to conditions that lead to colic.  These reasons have been discussed in the introduction.

Any condition that leads to the disruption of normal intestinal motility (lack of motility or increased or disorganized motility) can result in fluid and gas accumulation in the intestine. If this condition persists, the intestines, because of their poor attachments to the abdominal wall, may move to places where they do not normally belong. On their way to these abnormal locations, the intestines may twist or simply become lodged or trapped in areas that do not allow for the normal removal of the intestinal contents and gas.

In some situations such twisting or entrapments can also lead to the restriction or complete blockage of normal blood flow to and/or from a segment of the intestine. Primary inflammatory conditions of the intestine (enteritis) may also affect the intestines, leading to disrupted motility and dysfunction of the affected segment.  The disruption of intestinal function can itself lead to motility changes, pain, and abnormal function of other areas not directly affected by the inflammatory process. Inflammatory conditions may also affect the intestine secondary to intestinal displacement and/or restriction of the blood supply.  Therefore, a condition causing "colic" can cause a cycle of displacement, inflammation, loss of normal function and blood supply, and pain.

However, it is important to realize that movement of intestine to abnormal locations, entrapments, inflammation, loss of blood supply, and twists (volvulus) are not necessary in order for colic to take place.

About the Author

Bradford G. Bentz, VMD, MS, Dipl. ACVIM, ABVP (equine)

Brad Bentz, VMD, Dipl. ACVIM, ABVP, ACVECC, owns Bluegrass Equine Performance and Internal Medicine in Lexington, Ky., where he specializes in advanced internal medicine and critical care focused on helping equine patients recuperate at home. He’s authored numerous books, articles, and papers about horse health and currently serves as commission veterinarian for the Kentucky State Racing Commission.

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