When the Lean Construction revolution started about 25 years ago, it may not have considered the issue of corruption. The paper argues that corruption in construction forms a barrier in the implementation of Lean Construction. On the other hand, Lean Construction has the potential to combat corruption. Based on this contradiction, this paper shows how Lean Construction can be protected from corruption using something similar to a human immune system which includes Lean stem cells: transparency, accountability and integrity. Then paper shows how Lean Construction can play a vital role in combating corruption in construction via a Lean Anti-Corruption Toolkit.