How sound is the narration that mentions that Abu Muslim's concubine used to put poison in his food, and that he would protect himself from it by saying "Basmala" and the supplication: "In the name of Allah, the best of names, with whose name no disease can harm, Lord of the earth and Lord of the heaven"?

The account of Abu Muslim al-Khawlani drinking poison and surviving it is weak due to an interruption in its chain of narration.

As for what is narrated about Khalid ibn al-Walid drinking poison, there are weak narrations concerning it. The authentic narration states that he was brought poison, whereupon he said, "In the name of Allah," and then drank it. Imam al-Dhahabi and others authenticated this narration, and al-Bayhaqi titled a chapter concerning it: "Chapter on the protection from poison afforded by mentioning the Name of Allah, the Mighty and Majestic."