blood in poo and strange eating habit

Hi, I have a 13 week old male kitten. The last few days he has been eating excessively, even eating our other 4 year old cat's food. He has also been pooing much more frequenctly and heavily than usual. I also noticed tonight that there was a small amount of blood in his poo. Should I be worried? Any ideas greatly appreciated.
Thanks

Please call a vet ASAP.

Thanks for the prompt reply. I will. Any ideas on what this might be, as you can imagine, we're quite worried about him.
Thanks again

I have to agree , you need to take this kitten right away to the vet . Blood is never a good sign .

More than likely worms, but with kittens there are also other problems associated with blood in the stool. Should be checked by a vet.

We lost a little kitten 2 years ago, We didn't put together what was happening till to late. He ate way more than he had been and his little litter box smelled real bad. It turned out he was bleeding somewhere inside, we found out one night when he collapsed on the floor and had old bad smelling blood from his mouth all over, we rushed him to a animal hospital but there was nothing that could be done for him.