3 ms·

Can't the placebo also contain some form of dye?

• scheme271 1y ago
  It'll be a bit more complicated than that since the dye would have to get from your gut to your blood and then into the urine without breaking down and without other side effects. It's possible but probably not the easiest thing.
• cogman10 1y ago
  You'd be looking for a dye that survives in the blood and urinary tract and imparts blue/green colors to the urine and that isn't reactive or toxic. And generally speaking, when you are looking to treat something in a double-blind test, the control isn't placebo, it's the standard treatment. It's a tricky enough problem that when double blind studies have been done, the control will generally simply have a lower dose of methylene blue rather than no dose.