Is it permissible to conceal rare medicines from some people and sell them to others exclusively, or to refuse to sell an available medicine to those who request it for commercial or other reasons? Is it permissible to reserve large quantities of a specific medicine for a regular customer? And are the work and salary in such pharmacies lawful?

The basic principle is that the seller is not obligated to sell his goods to every interested buyer, and he has the right to refuse to sell them, or to stipulate selling one product with another. However, this may deviate from the principle if the pharmacist knows that the customer is in dire need of the medicine because his life depends on it, or if regulations organized for the public interest prevent it, in which case they must not be violated.

If the pharmacy owner does not seek what is permissible, the employee must avoid directly engaging in what is not permissible.

If the employee commits what is impermissible, he incurs sin, but this does not affect his earnings.

As for working in a pharmacy as an assistant without a certificate or a recognized qualification, merely based on experience, this is not permissible because regulations often prohibit it to protect people's health from the manipulation of unqualified individuals.