Usually tapeworm. The best thing to do is make an appointment with your veterinarian and try to take fresh clean stool sample with you. They will diagnose which type of parasite your pet has and give the correct treatment since different parasites have different treatments and there isn't any one that takes care of them all. Then, once your pet is cleared and you ever see the exact same thing again you can just call and pick up the meds most of the time (make sure it's the right one). They do have to be treated because otherwise they just multiply and cause the death of your pet so the sooner the better. The over the counter de-wormers (and flea meds) like the ones in grocery stores and pet stores are not recommended because they kill very few parasites and have an alarming tendency to kill the animal EVEN when the directions are followed exactly.
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