Therapeutic development and drug discovery processes are heavily challenged by delays in the preclinical experimental stages before being offered for Phase 1 clinical trials. Accelerating the preclinical phase via novel in-vitro systems is need of the hour to help provide effective therapeutics to cure diseases like cancer. Therapeutics to treat different diseases need to be developed through a systematic process to understand the uses, adverse effects, and mechanism of action of a prospective drug. Cutting edge computational models offer promising future tools. The Virtual Embryo like approaches may help reliable prediction and fast chemical risk assessment for the developmental toxicity testing domain. Recent advances in stem cell technologies may be used to reduce the use of laboratory animals and accelerate the testing of novel drug molecules along with immense future possibilities and improved research methods to work with. The following review provides an insight into the productive use of Embryonic Stem Cells, whether mouse or human, and how the use of stem cells technique has played a key role in improving drug development and therapeutics.