COUGH

Coughing is usually a hoarse/hacking sound with the head and neck extended and often "snaking" side to side. The cat may swallow once or a couple of times. Often nothing is produced. Occasionally the cat may end the cough with a gagging sound and some foamy white liquid.

 VOMIT

Notice the violent contraction of the abdominal wall and the moist gulping sounds followed by bringing up a volume of liquid. Some cats will howl right before they vomit.  Vomit can contain anything that your pet recently ingested (small fragments of hair, water, food, plant material, etc) or it can be yellow or green in color from bile. Most true "hairballs" only consist of clear liquid and a matted tube of hair. The action a cat makes while bringing up vomit or a hairball are very similar to each other, but different from that of a cough.