Deduction for Preventive health check-up:
Section 80D of the Income-tax Act provides a deduction in respect of premium paid on a health insurance of self, spouse and dependent children up to a maximum of Rs. 15,000 in aggregate. Further additional deduction of Rs. 15,000 (enhanced to Rs. 20,000 if parents are senior citizen) is also allowed for buying a health insurance policy in respect of parents.
From F.Y. 2013-14 payments made on account of preventive health check-up of self, spouse, dependent children or parents (s) during the previous year is also eligible for deduction which shall not exceed in the aggregate Rs. 5,000 prescribed in the section.
The above Rs. 5,000 deduction is included in overall limit of 15000/- or Rs. 20,000/- (as the case may be) of section 80D for health insurance and if you have already exhausted or used this limit for health insurance then you cannot claim additional deduction for preventive health check up.
However, the maximum deduction under Section 80D is up to 15,000, which also includes health insurance premium. In case parents are senior citizen, then the limit is enhanced to 20,000. If you are already claiming full tax deduction under section 80D then there is no additional tax benefit on preventive health check-up expenditure.