Cristy, new formulations of Kaopectate contain salicylates, which are similar to aspirin. Depending on the circumstances of exposure, large enough doses of bismuth salicylate could cause effects similar to aspirin poisoning. These include gastric irritation or ulceration, bleeding problems, seizures and liver damage.
Since many human medications can be harmful or even deadly to pets, the ASPCA advises pet owners never to give animals any medication or supplement that is not specifically prescribed for them by a veterinarian. If you suspect that your kitten may not be feeling well, you should call your vet so that she can be evaluated and given appropriate treatment.