African traditional medicine is not all magic, diabolic or Shirk. Africa like other continents of the world is blessed with herbs and roots that are very useful and potent for illnesses. Africans since antiquity have been treating their sick and curing ailments with the use of herbs. It's totally strange and unfounded for anyone to claim that the use of African herbs is entirely an act of polytheism. 

There are elements of diabolic practices and Shirk in African healing methods as there are in the healing methods of many people across the world too. In Africa, it is totally dependent on African spirituality and the belief that some illnesses are caused by evil eyes or curses and can only be cured through African exorcism which is inherently covered in practices that many would call diabolic and in our own religious perception, idolatry. In addition, it is dependent on the idea that healing comes from the Supreme-Being or the gods.

The important thing for a Muslim is to carefully observe the healing methods, learn about them, separate whatever has diabolic practices or magic in it and hold onto the others that are free from such. If Africans lose the values and benefits embedded in the African healing method, we would forever remain subservient to others who do not have a cure for ailments that our forbears have probably been curing thousands of years before the arrival of the criminal colonial slavers.