Mercuric Chloride (HgCl₂) is a very toxic heavy metal which induces oxidative stress-mediated Haematological disturbances. Jackfruit (Artocarpus heterophyllus (Lam.)) is a tropical fruit rich in bioactive and phytochemical antioxidants. This study evaluated the haematoprotective effects of Artocarpus heterophyllus fruit extract on HgCl₂-induced Haematological toxicity in Wistar rats. Thirty adult Wistar rats weighing 150-200 g were assigned randomly to five groups (n = 6) : control, HgCl, only (3 mg/kg), extract-only group (1000 mg/kg Artocarpus heterophyllus), extract+ HgCl, (extract administered 30 min before HgCl₂) and vitamin E HgCl, (200 mg/kg, administered 30 min before HgCl₂). Doses were administered orally for 28 days. Analysis of Body weight changes and Haematological parameters (erythrocytic indices, leukocyte profile and platelet indices) was conducted. The data were expressed as mean ± SEM and analyzed with one-way ANOVA followed by Tukey's post hoc test; P 0.05 was considered significant. Histological analysis of the blood was done using peripheral blood film and viewed in a microscope at 400x magnification. The administration of HgCl, significantly reduced weight gain, as evidenced by a significant decrease in body weight change when compared to controls (p = 0.0005) Compared to the HgCl₂-only group, weight gain was considerably increased by co-treatment heterophyllus extract. Significant haematological toxicity was caused by HgCl, exposure, as shown by decreased haemoglobin concentration (p = 0.0002) , red blood cell count (p = 0.0003) , platelet count (p = 0.0004) , plateletcrit (p 0.0001) and cell distribution width (p = 0.0013) There were in the leukocytes, such as a higher proportion of granulocytes (p = 0.0039) and a lower number of lymphocytes (p = 0.0187) Co-treatment with Artocarpus heterophyllus significant improved the alterations caused by the of HgCl₂-only. Histologically, HgCl, caused a reduction in the erythrocyte population and reduced the vacuole of the blood, this alterations where prevented by the co-administration of Artocarpus heterophyllus. Toxicity induced by HgCl, was prevented by the co-administration of Artocarpus heterophyllus confirming the protective properties of Artocarpus heterophyllus against heavy metal induced toxicity.