There is a story in 2 Kings which goes some way to answering this:
Death in the Pot
“38 Elisha returned to Gilgal and there was a famine in that region. While the company of the prophets was meeting with him, he said to his servant, “Put on the large pot and cook some stew for these prophets.”
39 One of them went out into the fields to gather herbs and found a wild vine and picked as many of its gourds as his garment could hold. When he returned, he cut them up into the pot of stew, though no one knew what they were.40 The stew was poured out for the men, but as they began to eat it, they cried out, “Man of God, there is death in the pot!” And they could not eat it.
41 Elisha said, “Get some flour.” He put it into the pot and said, “Serve it to the people to eat.” And there was nothing harmful in the pot.”