There is an interesting story in the book Charcoal Remedies.com where on pages 94 & 95 where a young girl who had severe UTI's since she was two and had a surgery where the doctor scraped the inside her bladder (ugh) and felt that she would need more surgeries. When the young girl was seven the mother gave her charcoal slurries for the first time and she has no longer had a UTI since.... :)
Here is a detailed testimony from a 79 year old retired engineer with kidney failure that might be of interest to you.
We do not believe charcoal [activated charcoal] CURES any disease common to man or animals. Charcoal is a natural remedy that does neutralize, adsorb, and/or remove thousands of different biological or man-made poisons from the body, allowing the body to better heal itself the way the Creator designed it to. Charcoal House LLC.
[But our websites, and hundreds of personal testimonies and research articles have gone a long ways to "cure" a lot of skeptics]