I had no idea about this, and it's made me come out all hot and cold! When Walter (who is now 8 years old) was about 18 months old he was poorly with a virus around the same time as my husband died, Walter loved John and quite naturally was grieving for him, and in that time an unneutered tom got in the backdoor and sprayed which stunk the place out but it also confronted Wally and scared him. Ever since then he's been a sprayer himself, he marks doors and windows the obvious in and out places, but he also does it on furniture and even on us, you name it he's done it. We have plastic in his favourite places because despite all we've (kindly) tried he just needs to do it, it must be his stress buster. BUT not long after he started, before we realised that he just wasn't going to give up we had an animal behaviourist come from the other end of the country to see him. Among her recommendations (including drugging the poor little soul - no thanks!) was a cocktail of these remedies. It made no difference to the lad, he pees to olympic standard, and we just grin and bear it and get the cleaning stuff out but I'm just thinking that if people who make their living recommending such things don't know about this, then the people who follow their advice might be doing more harm than good!
We tend to think these homeopathic things are safe as houses, but from time to time we find out they are not. Thanks for the tip off.