Take a walk through any pharmacy or natural health store, and you’ll find no shortage of products that will allegedly help you: from clarifying shampoo, to detoxifying teas and juices, and, at the more extreme end, supplements, enemas, and even colon cleanses. But before you succumb to this incredibly persistent and appealing notion, you should know that the idea of using some product to "detox" is gobbledygook.

A stem cell therapy has been approved for widespread medical use in the EU for the first time. The treatment - Holoclar - is used to treat a rare eye condition that can lead to blindness. It works in around 80% of cases.

After three decades of failure, researchers have found a treatment that greatly improves the prognosis for people having the most severe and disabling strokes. By directly removing large blood clots blocking blood vessels in the brain, they can save brain tissue that would have otherwise died, enabling many to return to an independent life.

Toshiba, the Japanese technology conglomerate with a lineage dating back to the 19th century, is looking for growth in a whole new way. In a sterilized clean room about 35 miles outside of Tokyo, where Toshiba used to make floppy disks in the 1980s and 90s, the company is now starting to grow thousands of lettuce plants as it expands into indoor agriculture.

The same cells that give Darek Fidyka his sense of smell are also helping him walk again. The man, who was paralyzed after a knife attack in 2010, can walk after doctors in Poland transplanted nerve cells from his nose into his severed spinal cord. The successful operation was the first of its kind for regenerative medicine, and Fidyka is believed to be the first man to walk again after having a completely severed spinal cord.

Meet the donors, patients, doctors and scientists involved in the complex global network of rare – and very rare – blood.