This product is absolutely amazing! I would not be able to keep a ferret without it! I've been using it on my ferret for about a year now and it reduced it's odour so much that I can barely smell anything... also the 'droppings' in the cage seem to lost its smell. Which is really good if you keep the pet indoors. I haven't noticed any side effects so far and hopefully I won't! The only downside is not about the product, but the customer services. I have been ordering the product for some time now and twice I got the wrong order.