The naturally-occurring bacterial enzyme Cocaine esterase, CocE, breaks down cocaine which reduced its addictive properties.
The discovery has been hailed as possible method of helping addicts get off the drug and could prevent deaths from overdose.
Scientists found the bacteria was only active in the body for a short while but a more stable version double mutant bacterial version known as DM CocE was more effective.
In the scientific trials on the ensyme, rats were trained to self-administer cocaine by pressing a button in their cage, mimicking the need for regular doses of the drug during addiction.
Rats treated with the double mutant form of CocE pressed the button to receive cocaine less often, suggesting that DM-CocE broke down the drug and dampened addiction.