Feline constipation can be very uncomfortable for both the cat and the owner. Cats suffering from feline constipation often cry when attempting to empty their bowels, act generally cranky, and sometimes scratch their rear-ends on the carpet or upholstery. 
For these reasons, both the cats and the owners usually want a fast cure.
Before a cure can be administered, it is important to determine whether or not the cat is actually constipated or may have a bowel obstruction (and therefore a total inability to empty the bowels). Feline constipation presents itself in the form of small, hard, pellet-like, difficult to pass, bowel movements. Many cats empty their bowels at least once, often twice a day. Just like people, however, each cat has its own rhythm, and some may only empty their bowels every couple of days. If you notice a change in your cats bathroom habits, constipation may be suspected.
Hairballs are a common cause of feline constipation. Along the same lines are minor obstructions such as digested paper or grass. These things mainly do harm by drying out the intestinal tract as they pass, thus causing the formed feces to be dry and painful to pass.
Moisture has a lot to do with bowel consistency. A cat must get enough water during its daily routine to sustain healthy body and organ functions--including bowel function. Counter-intuitively, wet, canned cat food can cause dry bowel movements by discouraging the cat to drink enough plain water. Sometimes cats drink too little water because they are finicky about the water's source or temperature. Sometimes changes in the home can cause a cat to stop eating or drinking enough to sustain healthy bowel function.
Changes in the home can also cause a cat to not want to empty their bowels. A disruption in daily routine, the movement of the
litter box, a new cat in the house, can all create anxiety in a cat and lack of interest in emptying their bowels can be a mental side-effect. 
Holding the bowel movement in too long can cause it to dry out, thus making it difficult to pass later. Keeping the litter box clean and in a private location in the home can help ease feline anxiety over using the litter box.
You can help a cat suffering from feline constipation by encouraging the cat to drink plenty of water. Mild laxatives can be administered by a veterinarian in more sever cases. Feeding your cat a high-fiber, dry cat food, and keeping your cat clean and brushed to avoid hairballs can also help fend off feline constipation. Do not despair, if your beloved feline friend may sound as if passing that hard bowel is killing it, chances are once it has passed and the original cause of the constipation is remedied, your furry friend will feel alright.
