The incidence of gastro intestinal disease is alarming problem all over the world particularly in third world countries like Bangladesh. Different tablet and liquid preparations are used to overcome the diseases. Different experiments are also conducted in different times on the different drugs of gastrointestinal diseases in the pharmacy lab. Among them some of the drugs are toxics. In a clinical trail the drugs are injected to the experimental animals and placebo are injected to the animals of the control group. All of drugs are measured on the basis of the results of the control group. The drugs are recommended on the basis of the results obtained from Meta analysis of series of trails. Meta analysis is the analysis of analyses which has combined the different results achieved from different analysis. Now a day, it has taken part in every important sector in our daily life by making pooled information through individual investigation. In this paper we have anticipated the side effects of different drugs used especially on gastro intestinal disorders through Meta analysis. Fixed effect model and random effect model have been used to draw inference regarding the side effects of the drugs by compared control group and experimental group. Meta analysis has been performed here to estimate the combined effect of toxicity. Moreover we have combined the effect size through forest plot which shows the results in graphical visualization.