The use of plants and spices extracts as herbal drugs to prevent and treat various diseases has been in practice in many studies. Therefore, this study was designed to study the role of cassia cinnamon bark extract on various physiological, biochemicals, hematological, immunological and histological changes in male albino rats in which, normal, hyperlipidemic and diabetic rats were used. During this study, seventy adult male rats weighting about 170-188g were randomly divided into seven groups each with 10 rats; each group was designed as follows: The first group was used as a control and was fed on standard diet and tap water ad libitum. The second group was treated with alcoholic cinnamon extract (500 mg/kg.bw). Third group was fed on high cholesterol diet (hyperlipidemic) while the fourth group was fed on high cholesterol diet and treated with alcoholic cinnamon extract (500 mg/kg.bw). The fifth group was injected with alloxan as a diabetic group. The sixth group was diabetic rats treated with alcoholic cinnamon extract (500 mg/kg.bw) and the seventh group; diabetic rats were treated with metformin drug (300 mg/kg.bw).