All perfect praise be to Allaah, the Lord of the worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.
Treatment with herbs is lawful. The Prophet, sallallaahu ‘alayhi wa sallam, explained that there is treatment for every illness. If Allaah The Almighty guides the patient to the correct medicine, it will be a cure for him by the permission of Allaah. [Muslim]
Usaamah ibn Shareek narrated that the Prophet, sallallaahu ‘alayhi wa sallam, ordered the Companions to seek treatment for illnesses. [Ahmad] These two Hadeeths, and others with the same meaning, prove the Sharee‘ah method of cure is dependent on causes. They also show that Muslims are ordered to seek treatment and that this is not contradictory to true reliance on Allaah The Almighty. However causes do not have positive affects in themselves, but only with the permission of Allaah The Almighty.
Going to astrologers or soothsayers to seek treatment with herbs is unlawful because this may result in their increase in number, along with their increased misguidance of the public. The herb-treatment that they offer is a cover up for the magic they practice and for the revelation they receive from devils.
As for going to them to find out unseen matters, this matter was previously ruled on in Fataawa 4987 and 7343.
And Allaah Knows best.