need help regarding my two kittens.

Me and my husband adopted two kittens last weekend. They are just over 3 months old. When we come home from work 9 times out of 10 one of the kittens have pooped and peed on our bed. Why do they do this and how do we stop this behavior? Also there poo is still runny with some blood in it. I've read it might be worms but they were de wormed before we got them. Is it true theh need to be dewormed every three weeks? Any help would be greatly appreciated

Bloody diarrhea is cause for a vet visit. Yes, it could be worms; but, it could also be coccidia or giardia. Need to make sure any medical issue is cleared first before trying to correct any behavioral issue.

With that said, it is very likely the accidents are happening because the kittens are not able to make it to the litter box in time. I suggest confining the kittens to a bathroom or small bedroom while you are gone to work (and at night while you sleep...just until the diarrhea is cleared up.). Somewhere that is pretty easy to clean/sanitize. Make sure you put their food, water, blanket/bed, and some toys in with them.

Speaking of food, are you feeding them what they were being fed prior to adoption? If not, did you do a slow transition to new food or did you switch cold turkey? Sudden food changes can cause GI issues.