Most of herbal formulations have lacking of preformulational and post formulational studies. Thus, an attempt was made to performed the preformulation and post formulation characteristics for senna leaf powder and calcium sennoside. The conventional tablet of senna leaf powder and calcium sennoside may release a significant amount of drug in the physiological environment of stomach before reaching at the site of action. Hence, enteric coated tablet of calcium sennoside and senna leaf powder was prepared using cellulose acetate phthalate for averting the initial loss of 5-8% sennoside in stomach. For this purpose different formulational factors were optimized. The in-vitro release of coated tablet was performed in 0.1 N Hcl and phosphate buffer of pH 6.8. After the enteric coating, the tablet ensured that it was more pH dependent and release the drug only at higher pH. This research work should be especially useful to professionals engaged in formulation development of herbal drugs, or anyone else who wants to perform the preformulation and post formulation study of herbal drugs.