Hairballs are tubular masses of hair which are typically a few inches long. Superficially, they may look similar in appearance to feces, but unlike stool they tend to be odorless.
It is very important to differentiate hairballs from other types of vomiting, and to differentiate vomiting from coughing. A cat’s vomit will often contain a small amount of hair regardless of the underlying cause of the vomiting. The presence of hair does not mean a vomiting episode is a hairball. Cats may vomit for many reasons, including dietary sensitivities, intestinal disease, cancer, and other metabolic disease processes. While the act of producing a hairball is often referred to as “coughing up”, hairballs come from the digestive tract (stomach and intestines). A true cough is caused by upper or lower respiratory disease (trachea and lungs). It can be difficult for owners to distinguish coughing from the vomiting of a hairball in some situations. A great way to help us determine what is actually occurring is by videotaping these episodes and bringing the footage in for us to assess.
In general, a cat should produce a hairball no more than once monthly. They may be slightly more frequent when cats are shedding, such as during seasonal changes. Cats should not vomit hairballs, or vomit period on a daily or weekly basis. Cats vomiting this frequently should be brought in for an exam and assessed for the possibility of gastrointestinal disease.