What is the ruling on working for a company that relies on direct marketing (network-tree marketing) for a medical product, and are the profits obtained from this work permissible (halal), impermissible (haram), or dubious?

It is permissible for a Muslim to take a fee for his work as a marketer or broker, as long as the commodity is lawful and the transaction does not involve anything prohibited by Islamic law. However, taking a commission for every subsequent sale merely for having introduced the commodity the first time is not permissible because no effort is expended, and it is advisable to avoid companies that operate on this principle.