A grieving father is suing a "naturopath" after his son died from leukaemia while following a "cure cancer with vitamins" therapy.
Mario Rodríguez, a physics student at the University of Valencia, was diagnosed with leukaemia aged just 21.
But ignoring conventional medical advice from oncologists, the young student abandoned chemotherapy and refused a bone-marrow transplant and instead sought out natural therapies.
He turned to José Ramón Llorente - the president of the Spanish Association of Orthomolecular Nutrition - who promised he could cure the cancer with vitamins under the principles of orthomolecular medicine.
The treatment cost €4,000 and involved using "fungi and alcohol," according to Mario's father Julián Rodríguez.
The doctor who initially treated Rodríquez, blamed the alternative medicine therapist for convincing the young patient to turn down a transplant and stop his chemotherapy.
He told El Pais newspaper that the treatments prescribed by the "naturopath" directly interfered with the young man's recovery, leading to an intestinal infection.
He died within six months but not before he told his father: "Dad, I was wrong".
Now his father Julián is taking Llorente, the "naturopathic specialist" who treated his son, to court in a landmark case and is lobbying for tighter government regulation of alternative therapies.
After initially rejecting the arguments, a regional court in February decided to hear the case.
"I want my son's case to serve as a way to initiate legislative change that regulates the advertisement, circulation and practice of these so-called 'alternative therapies'," the father wrote in the Change.org petition.
"For a car, a washingmachine, or a television, these products have to pass through pre-determined filters established by legislation. But to open a shady business and announce that you can cure cancer - no," wrote Julián in a message last year.
So far the petition has garnered nearly 56,000 signatures online. A growing number of people across Spain have launched protests against alternative medicines. Mario's own university, the University of Valencia, announced recently that it would cancel its master's of "natural medicine, acupuncture and homeopathy".
The Association to Protect the Sick from Pseudoscientific Therapies (APETP), which was started by Julián Rodríguez, praised the move on Twitter, saying "another one for science!"
La Universitat de Valencia, cancela la X edicion del "Master de medicina naturista, acupuntura y homeopatía"!! Otro tanto para la ciencia!— apetp (@apetp_) April 6, 2016
Last month, the University of Barcelona scrapped its own master's programme in homeopathic medicine due to its dubious scientific merit, as well as vocal opposition from students and faculty.
The tragic case of a six-year-old boy who died of diptheria last year also brought scrutiny to the alternative medicine movement. His mother worked at a homeopathic clinic and the parents had decided not to vaccinate him.