Abstract: Natural products have formed the basis of traditional medicine systems for thousands of years. Modern medicine improves on this process by extracting and concentrating the active compound from the natural product. An inherent problem with the widespread use of many natural products, however, lies with harvesting and processing products that have low concentrations of active principles however even though the concentration is low some active molecules are able to induce effects in the organism. The labeling of blood constituents with technetium-99m (99mTc) has been influenced by the presence of natural products. We evaluated the influence of a chayotte (Sechium edule) extracts (macerated and decoct) (i) on the labeling of blood elements with 99mTc, (ii) on biochemistry of blood (iii) and on the gauging of tail pressure in Wistar rats. In our study, the animals were treated with chayotte macerated and decoct extracts (100% v/v), as drinking water (15 days) and samples of blood were withdrawn. The blood samples were incubated with stannous chloride and with 99mTc. Plasma (P) and blood cells (BC) were isolated, also precipitated with trichloroacetic acid (TCA 5%) and soluble (SF) and insoluble fractions (IF) separated. There was a decrease in the radioactivity on the labeling of blood elements. Samples of blood from the animals which were treated with chayotte extracts were carried out with specific biochemistry kits and the blood biochemistry analysis compounds was done. It was analyzed the level of uric acid, albumin, cholesterol, creatinine, glucose, high density lipoprotein (HDL), globulin and trigliceridics. It was noticed that the extracts were capable of altering the levels of the non electrolytic substances in the blood. The gauging of the blood pressure of the animals was taken. Our results showed a reduction in the diastolic pressure. Concerning to results we suggest that the effect of chayotte may be influenced by the warmness. The effect of chayotte extracts probably, could be explained by the metabolization of the chayotte that could be capable of inducing the generation of active metabolites with oxidant property.