They started to turn to a yellowish color like all foam does after only 2 days, but this wasn't a big deal for me - all foam turns and they're covered by pillowcases. Not an issue. They needed to air out for a day or so because of that "new foam" smell, but it went away quickly. If you're looking for a set of relatively inexpensive pillows, compared to some of the others, then buy these. They aren't as firm as I had expected, nor as big, but they're still VERY comfy and help me sleep better.