? about kitty litter!?

I just got a new kitty. He is 6 w.o. today. He JUST started using a litter box 3 days ago. I've had lots of kitties in the past and never knew there could potentially be problems with kitty litter as I am reading. I understand they ingest it and this can cause problems. I am switching litters today but now I am worried he will have stomach problems. Like I said it has only been 3 days. Any advice? Will he be ok?