It's not a good idea to feed castor oil to cats. Most castor oil products, unlike the beans of the plant, aren't considered poisonous. However, ingestion of the oil can have a significant cathartic effect, and cause diarrhea and possibly vomiting. This could result in serious dehydration, particularly in a young kitten. We don't advise giving castor oil to your kitten instead consult with your regular veterinarian to get a recommendation for an appropriate remedy.