This one requires some documentation.
Here are the best numbers I could find in Arabs killing Arabs since 1948, mostly relying on Wikipedia.
| War | Year started | Low estimate deaths | High estimate deaths |
| Algeria civil war | 1954 | 150000 | 800000 |
| North Yemen Civil War - Eg | 1962 | 100000 | 126000 |
| Black September, Jordan | 1970 | 2000 | 25000 |
| Sahara war | 1975 | 10000 | 24000 |
| Lebanese Civil War | 1975 | 130000 | 250000 |
| Libya Egypt war | 1977 | 500 | 500 |
| Iraq under Saddam | 1979 | 600000 | 800000 |
| Hama massacre, Syria | 1982 | 17000 | 40000 |
| South Yemen civil war | 1986 | 10000 | 10000 |
| Iraq invasion of Kuwait | 1990 | 1000 | 2000 |
| Yemen civil war | 1994 | 7000 | 7000 |
| Yemen - Sa'adah Insurgency | 2004 | 5000 | 8300 |
| Hamas-Fatah fighting | 2006 | 600 | 600 |
| Lebanon Camps | 2007 | 275 | 275 |
| TOTAL | 1033375 | 2093675 |
As you can see, estimates vary wildly for many of these events. I pretty much took the midpoints for the purposes of the chart, estimating about 1.5 million Arab deaths. (There have been perhaps 60,000 Arabs killed in all the Arab/Israeli wars combined including the intifadas.) I tried not to include Kurdish deaths nor those Arabs killed by the French during the Algerian war - much of that war was a civil war as well. I also did not include the Iran/Iraq war at all since that was not Arab on Arab violence, and Muslim on Muslim deaths is an entirely different set of numbers.