A health problem or ailment regarding the insured, that existed before the date of the insurance policy cover became effective. It is an ailment or disease that a person is already suffering from at the time of purchasing health insurance. Each health insurance company uses its own particular definitions of pre-existing condition. In addition, a coverage limitation included in many health policies with respect to pre-existing diseases, which states that certain physical or mental conditions, that are previously diagnosed, or which the individual has availed treatment for, prior to the issue of the policy and the existing ailment, is a complication of previously occurred ailment. It may not be covered under the new policy for a specified period of time.