This shows there was drug use in Ancient Egyptian culture. As for the cocaine the best story goes that there was some sort of ancient world trade at that time. Why it stopped no one is real sure. Most all think that it is still impossible even though some evidence leans to this.
It seems some say the mummies where some how contaminated and they refuse to believe it. Yet even stranger and one thing they cannot ignore is that a lot of them have tobacco in their system. Which was another plant that wasn't discovered until columbus.
Another theory is there was an old form of this plant that somehow disappeared without a trace, which doesn't seem very likely.
Another theory is that boats went from South America directly to Africa trading these goods, also very unlikely.
To me somehow this had to happen. If you find traces of these drugs in the mummies then they took the drug, period. It had to get in there somehow and that means, in my opinion, the drugs came from South America. Probably on some ancient trade route from China.