You need to specify a time period. In England there were no apothecaries or alchemists before the 14th century and witchcraft was not really acknowledged before the 13th. Remedies, treatments and medicines in the 12th century came from monastic infirmaries, from local midwives and wise women, from hugely expensive physicians, or from the countryside - folk remedies were widespread and established long before apothecaries came along.
For researching the types of medical treatments used in the 12th century you could look to the Trotula (written in Salerno but widely circulated around Europe), found in almost
accurate translation here: https://isidore.co/calibre/get/pdf/The% ... __4855.pdf
Then there is the Chirugia ("Surgery") compiled by students of Roger Frugard in about 1180 and again widely circulated around Europe for at least the next century. Elements of this can be found in Tony Hunt's book The Medieval Surgery - Boydell Press 1999.
Monastic medicines have not been sufficiently researched or published, yet they were a hugely important factor throughout the medieval era. Every monastic house had an infirmary, along with herb gardens, intended originally to house and treat elderly, infirm and sick monks, but charitable care was also extended to guests and any locals (including aristocrats and kings) who might seek medical help. This is an area sadly neglected by historians, who seem fixated on the later mysteries of alchemy. Furthermore, almost all medical texts and books of herbs were to be found only in monastic libraries, such as this sample: https://publicdomainreview.org/collecti ... ollection/
This news report is significant: http://news.bbc.co.uk/1/hi/health/3745498.stm
Literacy had a great impact on medical matters - at this time most people outside the Church were illiterate and therefore unable to access documents in Latin, so physicians needed to undergo a Church education before they could set up practice. Midwives and wise women worked entirely with folk remedies handed on by word of mouth.
Finally, it is worth remembering that enormous value was placed on the power of prayer and religious ceremonies in healing the sick - perhaps more than any medicines or surgical treatment.