Maybe people can drink Colloidal Silver in water for ringworm, and the same for cats. I have taken lots of it for other reasons mixed with water. There are warnings it can cause blueing of the skin, but I never had it apparent. I put it topically on ringworm of the feet before. The only thing that worked for me with ringworm was aloe vera juice or olive leaf with parasite herbs like garlic, Black-Walnut , GSE, parsely. The aloe vera juice and olive leaf alkinilize the body creating an expelling flow to rid the ringworm protozoa.