In
the 19th century is was assumed that organic compounds could only be
produced by plants and animals. These compounds all had carbon and
hydrogen in common. Some organic compounds also include O, N, the
halogens, S and a few other elements.
Now we know that organic compounds can be synthesized in the laboratory.
Simple compounds of carbon and hydrogen include the alkanes and
alkenes, for instance, as well as aromatics like benzene. But oxygen is
a common element in organic compounds like alcohols, aldehydes, ketones
and ethers.
So the bottom line is that all organic compounds contain C and H and
some contain O as well, but O is not required to be an organic compound.
========= Follow up ==========
Why are these people saying "yes". It's obvious that there are many organic compounds that don't contain oxygen
