Machine intelligence concepts have revolutionized the way to solve/address the multifaceted problems in many domains such as network security, 3-D modelling, etc. One domain which profoundly benefits from these algorithms is Medical Science. To solve the noise and contrast issues in medical images, we have reviewed different implementation and variants on CLAHE based enhancement techniques. Implementation of CLAHE based techniques in medical images is reviewed extensively in this paper along with its usage in other fields is also highlighted. Different algorithms are measured on performance parameters like Entropy, SNR, PSNR etc.