The example that springs to mind is that of what Camillo Golgi proposed. Upon examination of a prepared glial cell under a light microscope, he proposed the nutritive hypothesis about the role of the glial cells in light of which they seem to be attached to the blood vessels of the brain. He proposed that it was via these gial cells that nutrients would actually be distributed throughout the rest of the neuronal systems. In modern research, this is deemed unlikely because of the five barriers that the nutrients would have to travel through before being finally assimilated to the nervous network. The current paradigm is that nutrients are dissolved in the “gaps” between the different cells, and this allows higher efficiency. So Golgi, not pseudoscience, just unlikely.
So who exactly is calling this pseudoscience?
Just spitballing here, but I remember reading a passage in Martin Gardner’s Fads and Fallacies in the Name of Science about “light therapy”, which was riddled with pseudoscientific babble about frequencies and whatnot in order to justify paying somebody to shine coloured light on an ailing body part. Nowadays there is serious study in the field of phototherapy.
Anyone in chemistry 
Didn’t we just get done saying that scientists don’t normally use the word pseudoscience? Why don’t you cite some examples if you think that’s wrong?
And it also sounds as if you’re saying that Golgi used to be thought correct but is now considered at least “unlikely”. Which is the opposite of what this entire thread is about. We’ve been talking about pseudoscience that is now accepted. Is that what you mean or not?
My argument was both true and relevant. Sadly, the relevant part wasn’t true and the true part wasn’t relevant.
Hey, they can’t all be gems! 
Those are just about 99% different things.
When proposing potential psuedo-science fields, it is a really good idea to think about what the hypothesis proposed is. Most of the examples above are not mentioning the hypothesis, they are looking at the manifenstation of the results of the hypothesis. Which is a very different thing.
Phototherapy is a grab bag of different proven treatments that have really only one thing in common - that they use electromagnetic radiation in the visible range. There is no unifying hypothesis for them, and the individual treatments don’t really interrelate. But the “light therapy” stuff was based upon a core idea that was basically hokum. If it did any good it would have been by coincidence, and had nothing to do with the ideas by which it was supposed to work. So chalk and cheese.
You’re probably thinking of Spectro-Chrome Therapy “discovered” in 1920 by Colonel Dinshah Pestanji Framji Ghadiali.
This is a fine example of what Francis Vaughan keeps trying to get across. Science tries to establish a mechanism and uses testing to prove or disprove that mechanism. Quacks just invent and make claims. Of course people will try to use scientific words and phenomena to advance their quackery. Gardner documents a long history of so-called color therapies and sets it after a section in which radio waves were another source of magical healing properties. Those started around 1920 when radio became a major buzzword, much like quantum is a major buzzword in quackery today.
You absolutely can’t make the leap from using electromagnetic radiation being considered quackery to its use being scientific. The claims have nothing in common except the words used to describe them. And the quacks certainly didn’t come first. The science came first and quacks appropriated it.
I think parapsychology is unique-it went from pseudscience, to a “mildly” accepted branch of psychology, and back to pseudoscience. The period in which it was accepted as a science was brief…from about 1930 to about 1970. This coincided with the career of Dr. J. B. Rhine-who’s experiments in the 1930’s-50’s appeared to show some validity.
Subsequent to this rigorousresearch showed that there was no validity, and parapsychology is now felt to be bunk.
I don’t think it was accepted as science in that period. Some people may have accepted it, but they were a minority. aside from the few making it into respected journals like Science or Nature, you wouldn’t find Psi articles in any of the abstract indices. And in 1952 Martin Gardner published his In the name of Science, which set down the case against Rhine. C.E.M. Hansel’s articles came out in the 1960s, and his book ESP: A Scientific Evaluation in 1966.