The use of natural materials for healing is possibly as old as mankind with the oldest evidence dating back to the Neanderthal era (70,000 BC) found in Shanidar Cave of Iraq. People on all continents have used hundreds of indigenous plants for treatment of ailments since prehistoric times. This knowledge could have arisen out of observing lower animals in disease and by trial and error. Thus the use of plants as medicine predates written human history. A fundamental difficulty of studying ancient history is that recorded histories cannot document the entirety of human events and only a fraction of these documents have survived to the present day. Furthermore the reliability of information obtained from these surviving records must be considered. It is also essential to take into account the bias of each historian.

Going by written records, the study of herbs dates back to about 5,000 years to the Sumerians, who have described well-established medicinal uses of plants like laurel, caraway and thyme. Ancient Egyptian medicine of 1,000 BC is known to have used garlic, opium, castor oil, coriander, mint and indigo for medicine and the Old Testament also mentions cultivation of herbs including mandrake, vetch, wheat, barley and rye. Ancient medical documents like Ebers Papyrus (1500 BC) and the Kahun Medical Papyrus have recorded the use of several commonly used herbs by ancient Egyptians.