Hello Hassan,   Zocor, an HMG-co reductase inhibitor/member of the statin family of drugs, is used, as you may know, to reduce your LDL cholesterol levels.  Reduction of LDL cholesterol is one way to help prevent heart disease.   Common side effects of the statins include muscle aches, and in very few people this can progress to rhabdomyolysis, a serious condition where muscle tissue breaks down.  Also, statins can raise liver enzymes and should generally not be used in people with liver diseases.  Your doctor should monitor your liver enzymes with a blood test while taking statins.   Use with the fibrate class of drugs (fenobrate, or Tricor as an example) should be cautioned against, as the rate of rhabdomyolysis is increased.  Also, significant amounts of grapefruit juice ingestion can unpredictably raise the amount the drug level in the blood and should be avoided.   To your health, Neil MD