Cyclosporine is an immunosuppressant usually used to prevent renal transplantation rejection. Nephrotoxicity and hypertension are considered as the most frequent side effects of cyclosporine treatment. The neurotoxic effects of cyclosporine such as agitation, anxiety, delirium, depression and psychosis have recently been found. Methylprednisolone may increase as well plasma concentration of cyclosporine, which leads to side effects. Here we report a $Henoch-Sch"{o}nlein$ nephritis patient treated with cyclosporine and methylprednisolone who has experienced psychosis including visual and auditory hallucination and convulsion.