Human urine odor can be eliminated by washing the affected item with a cleaner that contains enzymes that destroy uric acid crystals. If the item to be washed is clothing, pre-soaking prior to washing in the hottest water possible is also effective in helping to remove urine odor.
To pre-soak white clothing, mix 1/4 cup of chlorine bleach with 1 gallon of water, and soak the affected articles of clothing for several hours before washing. For colored clothes, use a mixture of 1/4 cup of non-chlorine bleach in 1 gallon of water. Enzyme-based spray products marketed for removing pet urine from furniture and carpets are also effective at eliminating human urine order, as all urine odor is caused by the same uric acid crystals and bacteria.