The mobile computing and cloud computing together form into Mobile Cloud Computing (MCC). The mobile devices have some limitations like computation power, battery life, etc., These limitations can be overcome by integrating with the cloud technology. Even in this case, delay will be introduced due to WAN properties during the offloading process of the tasks from mobile environment to cloud environment. This is reduced with the use of cloudlet environment. In this paper, fault tolerant dynamic task offloading with cloudlets in mobile cloud computing is proposed. The technical process of resisting against diseases by the human is incorporated in MCC to fight against the faulty machines in the system. The proposed system is simulated using openstack++ and evaluated in terms of task completion time. The performance of the proposed system is compared with the algorithm where rescheduling is not carried out and DR approach [28] and is proved to be performing better.