Pros: Safe and widely available
Cons: Slow acting, and moderately effective at best.
Nature's Miracle is an enzyme solution type product (see below) Of all the enzyme type products I have used, I found it to be one of the least effective and highest priced available.
Given the choice between NM and nothing, I would certainly purchase Nature's Miracle again. It does mitigate the odor. However, in the future when I need an enzyme product I will look elsewhere.
Natures miracle is applied by saturating the affected area with the solution. It is important to note that in carpeting the affected area below the surface may be 6-8 times larger then the visible spot/stain. 8-16oz per application is normal and the product should be re-applied until the odor level stops decreasing. 3-4 applications is typical and a gallon will treat 4-8 spots.
Multiple applications is normal, but each spot required multiple re-treatments with Nature's Miracle to achieve the same level of odor abatement provided by a single 8-16oz application of the 'budget' enzyme product (PetZyme).
At $19.99 per gallon Nature's Miracle is roughly twice the price of PetZyme ($9.99/gal) and 33% more than most other competitors ($14.99 - $16.99/gal).
Nature Miracle has a floral smell that is somewhat of a a cross between handsoap and the air freshener in a porta-john. While not unpleasant initially, after awhile it becomes more and more offensive. Once on your hands the fragrance will remain on your hands for 8-12 hours unless you rinse you hands with lemon juice.
Most effective on:
Enzyme solutions are the best option for wearable/washable items such as cloting, and items that should not have harsh chemicals such as bedding, etc.
Subsequent inspection with a handheld blacklight (see below) revealed that Nature's Miracle leaves behind a great deal of residue in the carpet even after shampooing. No analysis was performed, but it appears to be some sort of soap. This is a negative because soapy residue in carpeting captures dirt more easily leading to 'dingy' carpet and premature wear and tear.
Notes about Odor Removal products
Pet odor removal products generally fall into one of four specific categories. Chemical modifiers (Odor Destroyer, Oxy Clean), Enzyme solutions (Natures Miracle, PetZyme), cover up fragrances (Fabreeze, Lysol), and home remedies (vinegar, ammonia, bleach, etc).
Enzyme solutions like Nature's Miracle work by introducing beneficial bacteria to digest the proteins present in pet urine and feces. Left untreated, naturally occurring wild bacteria will take root and begin feeding off the proteins. These wild bacteria give off ammonia like gasses which all know as "pee odor". The advantages of enzyme solutions is that they are safe in almost all applications and widely available. The Disadvantages is that they are slow acting (up to 14 days per treatment) and cannot handle old/ serious odor problems.
Chemical Modifiers like Odor Destroyer work by chemically breaking down the proteins present and (typically) killing off any living bacteria. The advantage of chemical modifiers is that they are far more effective at removing odors, and less expensive in the long run. The disadvantages of chemical modifiers is that they are typically harsh chemical mixtures and do not remove stains (remove by shampooing after odor treatment) Also, pets and children should be kept away from the area being treated.
Cover-ups like Fabreeze merely try to prevent your nose from smelling the odor by temporarily overpowering your senses with a stronger smell. They do not remove the source of the odor, and may cause an animal to re-mark the area to freshen up their marking. Cover ups are not a viable solution and should be avoided.
Home remedies are almost never effective and often make the problem far worse. Several make the smell permanent, and some damage carpeting, upholstery, and sub-flooring. Unless you want a really stinky mess on our hands, avoid these at all costs. The most commonly unsuccessful home remedies are vinegar, ammonia, and a 'secret formula' concoction of hydrogen peroxide and baking soda.
Cat urine, soap, soda, and many other materials glow under a fluorescent black light. Because of this a blacklight is an effective tool for locating liquids and their residue in household carpeting. Plug in fluorescent Blacklights are available at home centers like Home Depot, Lowes, etc. and OdorDestroyer.com carries an inexpensive handheld unit that is powered by AA batteries.