In and of itself, a bout of loose stools isn't necessarily cause for alarm. Stress or a change in diet can easily give your cat the runs for a day or two. Occasionally it happens to the best of us, am I right? (Never give your cat dairy products like milk. These are guaranteed to upset your cat's tummy.)

Diarrhea as a stand-alone problem can cause dehydration and loss of electrolytes, but this isn't a concern right away. The bigger issue is that it could be a symptom of another, more serious problem.

How do you know if it's time to take your cat to the vet?

• The diarrhea is bloody. Check the litterbox leavings carefully, looking for blood which is red (fresh) or black (from internal bleeding).
• Your cat shows other signs of illness. Is your cat listless? Has she lost interest in food or water? Do her eyes seem dull and/or goopy? Runny nose? Sneezing or coughing? Are her gums pale? If you gently press her chest and abdomen with your hands, does she cry out?
• The diarrhea has persisted for more than 48 hours. Even if the root cause is minor, after 48 hours of diarrhea your cat can suffer from dehydration. The vet can give her a dose of subcutaneous fluids and electrolytes to help her through it.
• Your cat can't make it to the litterbox and loses control of her bowels suddenly, everywhere, and repeatedly.

If your cat shows any of the above signs, call the vet right now to make an appointment.

If your cat seems perfectly fine aside from the diarrhea, take away her food and wait 24 hours. Be sure she has easy access to clean, fresh water, in a clean bowl. Watch her for other symptoms, and make sure she's kept warm and out of drafts. If your house is chilly, you might want to keep her confined to a separate room with a space heater. (Needless to say, if she's an outdoor cat, keep her inside.)

If she seems alright the next day, give her a little bit of food. Not too much - she'll be liable to stuff herself, and make the problem worse. Return her to her regular diet gradually over the next 24 hours. If she still has diarrhea 48 hours after you first noticed the problem, then take her to the vet.

Diarrhea is a much more serious problem for kittens than it is for adult cats. An adult cat can easily go 24 hours without eating, although you wouldn't know it to hear them complain about it.

It's common for kittens to suffer a tummy upset after being brought home. Keep them in a calm, quiet place, and feed them the same brand of food they had been eating before. (You can call the shelter or breeder to find out what they had been feeding.)

If your kitten still has loose stools the next day, or if it shows any other symptoms, take them to the vet immediately. The cause may not be serious, but a little kitten doesn't have the physical resources to tough out the loss of fluids.