Medical reimbursement is considered as income?

my mother is suffering from chronic kidney disease and is on peritoneal dialysis. my employer gives me the reimbursement for the medicines used in the dialysis procedure. the amount reimbursed was around 350000 ( three lakh fifty thousand). the salary section has included this amount in my gross annual income and taxed me heavily. please clarify if the reimbursed amount will be considered as my income ?. how can the reimbursed amount (which is the actual amount incurred) be taxed?