What is the name of the ancient Greek goddess of medicinal herbs?

The name of the ancient Greek goddess of medicinal herbs is Panacea. In Greek mythology, she is often depicted as a figure who has the ability to heal all ailments, representing the concept of universal remedy. Panacea is associated with the healing properties of medicinal plants and herbs, which underscores her significance in ancient medical traditions.

Hippocrates is a foundational figure in medicine and often referred to as the "Father of Medicine," but he is not a goddess or personification of medicinal herbs. Euphrates is a river in ancient Mesopotamia and does not have relevance to Greek mythology or medicinal herbs. Pandora is known for her role in Greek mythology as the first woman and the bringer of misfortunes, rather than a deity associated with healing.

Thus, Panacea stands out clearly as the correct choice, symbolizing the age-old search for healing and medicinal knowledge within the context of ancient Greek culture.