The study analysed 150 mummies and found that ancient embalmers also didn't always leave the mummy's heart in place, the Fox News reported.
The study co-author Andrew Wade, an anthropologist at the University of Western Ontario said that the study contradicts the findings by Herodotus, who got an inside peek at the Egyptian mummification process and described multiple levels of embalming.
Herodotus described multiple levels of embalming: The elites, he said, got a slit through the belly, through which organs were removed. For the lower class, mummies had organs eaten away with an enema of cedar oil, which was thought to be similar to turpentine, Herodotus reported.
In addition, Herodotus claimed the brain was removed during embalming and other accounts suggested the heart was always left in place.
Wade and his colleague Andrew Nelson looked through the literature to see how eviscerations really took place and also conducted CT scans and 3D reconstructions on seven mummies.
The team found that rich and poor alike most commonly had the transabdominal slit performed, although for the elites evisceration was sometimes performed through a slit through the anus.
They also found that there wasn't much indication that cedar oil enemas were used and only a quarter of mummies had their hearts left in place.
They also found that about a fifth of the brains were left inside the mummies' skulls.
The research has been published in the February issue of HOMO - Journal of Comparative Human Biology.