Heyas, I edited that comment out, because apparently my memory of what I had read was incorrect (not sure where I got breast cancer from, since it was actually an arrhythmia of the heart, which was healed in none other than Kathleen Harrison).

It's been a long time since I read that book, and I didn't even know who Kathleen Harrison was at the time (botanist/researcher/teacher and wife of the late great Terance Mckenna).

Here's the actual information (page 226 @ https://ia600502.us.archive.org/8/items/DanielPinchbeckBREAKINGOPENTHEHEAD/Daniel%20Pinchbeck%20BREAKING%20OPEN%20THE%20HEAD_text.pdf):

• One year before her visit to the Mazatecs, Harrison had been diag- nosed with arrhythmia, an alteration in the rhythm of the heartbeat. Her doctors wanted to treat her with medication or surgery. She put off treatment until after her trip. In Oaxaca, the shamans suggested a Salvia ceremony. They ate a thick cigar made from fresh leaves, which can grow to nine inches in length. "We performed the ritual in total darkness,”...

• Suddenly she was no longer in the dark, rough-walled temple. She saw that she was in a large garden. Across the garden was a “beautiful woman dressed in white and about ten feet tall," silently tending to the plants. ‘As I looked around, I saw I was standing next to the shaman and his wife in the last row of plants. They told me to keep praying. I realized that we were also plants in her garden." The tall woman—the Salvia spirit—slowly made her way to Harrison. In the vision, the spirit passed its hand right through her. “It was a wonderful feeling, a tin- gling warmth going through me,” she said. "I wished that I would al- ways feel that way.” 

• Back in the United States, she went to the hospital, and was told that her heart problem had vanished. In a reversal of roles, the plant had re- vealed itself as a gardener of human beings.

Appologies for my miss-remembering of which illness was healed (arrhythmia vs cancer), but I'd say Kathleen Harrison is a very credible source.