According to the medical insurance policy, when the balance of medical insurance personal account is zero, the insured person can not enjoy the treatment of overall payment when purchasing drugs at designated pharmacies. This means that when the balance of medical insurance personal account is exhausted, the insured must bear the cost of purchasing drugs at designated pharmacies, but not through the medical insurance pooling fund.

The purpose of this regulation is to prevent unreasonable use and waste of medical insurance funds. The medical insurance pooling fund is established to ensure the reasonable payment of the medical expenses of the insured. If individuals are allowed to use the overall fund to pay after the balance of the medical insurance account is zero, it may lead to unnecessary consumption and abuse of the medical insurance fund.

To sum up:

After the balance of medical insurance personal account is zero, the insured person can not enjoy the treatment of overall payment when purchasing drugs at designated pharmacies. This regulation is to prevent unreasonable use and waste of medical insurance funds.

Legal basis:

Article 29 of the Social Insurance Law of People's Republic of China (PRC) stipulates: "The part of the insured's medical expenses that should be paid by the basic medical insurance fund shall be directly settled by social insurance agencies, medical institutions and pharmaceutical business units."

Article 32 of the Regulations on the Basic Medical Insurance for Urban Workers in People's Republic of China (PRC) stipulates: "The part that is not paid by the personal account shall be paid by myself."