How do you know when a situation is critical enough to find a veterinarian immediately? Anything is worth at least a call if you are not sure what is wrong, but some things require urgent attention. Here are some signs that should have you heading for the emergency clinic:

*Seizure, fainting or collapse.

*Eye injury, no matter how mild.

*Vomiting or diarrhea -- anything more than two or three times within approximately an hour.

*Allergic reactions, such as swelling around the face, or hives, most easily seen on the belly.

*Any suspected poisoning, including antifreeze, rodent or snail bait or human medication. Cats are especially sensitive to insecticides (such as flea-control medication for dogs) or any petroleum-based product.

*Snake or venomous spider bites.

*Thermal stress -- from being either too cold or too hot -- even if the pet seems to have recovered. (The internal story could be quite different.)

*Any wound or laceration that is open and bleeding or any animal bite.

*Trauma, such as being hit by a car, even if the pet seems fine. (Again, the situation could be quite different on the inside.)

*Any respiratory problem: chronic coughing, trouble breathing or near drowning.

*Straining to urinate or defecate.

Although some other problems are not life- threatening, they may be causing your pet pain and should be taken care of immediately. Signs of pain include panting, labored breathing, increased body temperature, lethargy, restlessness, crying out, aggression and loss of appetite. Some pets seek company when suffering, while others will withdraw. When in doubt, err on the side of caution.