There was no autopsy done on Arafat's body. If the Palestinians truly suspected Israel of any foul play, they would have jumped at the opportunity to prove that Arafat was poisoned. The fact that they choose not to do so speaks volumes.
Read from Israel Matzav:
Al-Jazeera suggests Arafat poisoned by Israel
Arafat's widow provided Al Jazeera with his clothing and toothbrush for laboratory testing at the Institut de Radiophysique in Lausanne, Switzerland. “I can confirm to you that we measured an unexplained, elevated amount of unsupported polonium-210 in the belongings of Mr. Arafat that contained stains of biological fluids,” Al Jazeera quoted Dr. Francois Bochud, the director of the institute as saying.Of course, severe diarrhea, weight loss, and vomiting are all consistent with the final stages of AIDS as well. But al-Jazeera would never report that.
According to the report, Russian spy-turned-dissident Alexander Litvinenko, who died in London in 2006 under suspicious circumstances, was found to have been poisoned with polonium slipped into his tea.
Arafat suffered similar symptoms to Litvinenko prior to his death - severe diarrhea, weight loss, and vomiting, according to the report.
Palestinians and Arabs have charged in the past that Israel poisoned Arafat. Some PA leaders have suggested that former Fatah official Mohammed Dahlan assisted Israel in the poisoning.
The Al Jazeera commissioned study of Arafat's belongings did not reveal any traces of common heavy metals or conventional poisons, so they turned their attention to more obscure elements, discovering the high levels of polonium, according to the report.
UPDATE: I wonder what evil scheme they have up their sleeves:
Palestinians consider Arafat autopsy eight years on.