he didn't kill millions. by the estimates provided by the kurds which can be argued as tainted, they say 300k. but if "millions" ads drama and impact to your arguments by all means say it.
Don't know how accurate this is:
Kill tally: Approaching two million, including between 150,000 and 340,000 Iraqi and between 450,000 and 730,000 Iranian combatants killed during the Iran-Iraq War. An estimated 1,000 Kuwaiti nationals killed following the Iraqi invasion of Kuwait. No conclusive figures for the number of Iraqis killed during the Gulf War, with estimates varying from as few as 1,500 to as many as 200,000. Over 100,000 Kurds killed or "disappeared". No reliable figures for the number of Iraqi dissidents and Shia Muslims killed during Hussein's reign, though estimates put the figure between 60,000 and 150,000. (Mass graves discovered following the US occupation of Iraq in 2003 suggest that the total combined figure for Kurds, Shias and dissidents killed could be as high as 300,000). Approximately 500,000 Iraqi children dead because of international trade sanctions introduced following the Gulf War.
. . .
http://www.moreorless.au.com/killers/hussein.html