The habit of Catha edulis chewing has prevailed for centuries among populations in the horn of Africa and the Arabian peninsula causing many social and economic problems. The present study evaluate the effects of fresh leaves khat on both serum glucose, plasma lipid profile and histopathology of liver. The results showed that feeding with khat leaves reduced total serum cholesterol, HDL-and LDL cholesterol levels and glucose concentration. After khat withdrawal cholesterol and HDL-cholesterol levels were still significantly decreases , whereas serum glucose content was non significant and LDL-cholesterol concentration was significantly increases compared to control group. While, the khat intake had significant elevation on triglycerides serum content and remain elevated after withdrawal from khat. There were histopathology changes confirm the toxic effect of the khat. After khat-withdrawal there was normalizing for most of these alteration, confirm diverse and adverse effects of khat.

Cyclosporine A (Cs-A) is a frequently used immunosuppressive agent in transplant medicine to prevent rejection and in the treatment of autoimmune diseases. Vitamin c is a potent antioxidant that has the ability to scavenge factors causing free radical formation in animals receiving Cs-A. It play a major role in disease prevention. Cs-A induced histological and ultrastructural alterations in the pulmonary tissue. These included congestion and hemorrhage of most blood capillaries, increased number of lymphocytes within the thickened interalveolar septa and destruction of the inner border of the respiratory bronchioles and increase of collagen fibers. Changes were seen in type I& II alveolar cells in the form of vacuolation, increase in the number of lysosomes, shortening of the apical microvilli and irregularity and swollen of the nuclei. Also, an increase in number of macrophages and fragmentation of the rough endoplasmic reticulum. Most of the main cell types in the alveolar tissue had restored their normal histological and ultrastructural appearance by VC. Conclusion: Antioxidant nutrients (VC) can improve lung histological and ultrastructural damage produced by Cs-A administration.