My kittens had diarrhea since last night not constant they are on erythomicin and clavamox and we have them on fancy feast kitten and kitten chow do you think it is a change of food or medicine. Calling vet later.
Good that you are calling the vet! Please keep them hydrated by giving them unflavored Pedialyte (electrolyte replacer) diluted 50/50 with bottled, filtered or good well water. Dehydration sets in quickly at that age & can have a domino effect on their health. If you don't have unflavored Pedialyte on hand, you can use the recipe at www.kitten-rescue .com.
As far as causes, there are many. Are you diluting their food with a kitten milk replacer? In my experience, goat milk based formulas are better tolerated than whey based. Fresh, raw goat milk is great used as is; I also use canned or powdered goat milk in a 'glop', using the formula at kitten-rescue. com (that is our TCS member Hissy's website). Changing foods to suddenly is often a culprit as are the antibiotics.
You can try adding a bit of canned pumpkin and see if that improves things. Normally, the thing to do is to give the guts a rest by feeding boiled chicken or ground beef broth for a day then slowly adding the meat with boiled white rice. Because kittens have such a high caloric and nutritional demand, you would have to feed much more often.
When asking your vet, you can inquire about using red raspberry leaf tea or slippery elm decoction. I have also used PetLactin, which is like the old-fashioned kaopectate with kaolin and pectin.
Please let us know what your vet says!