It's a common knowledge that if a fly falls into your food or drink, you probably shouldn't drink it because it might cause food poisoning. This might be a myth itself but that is not what I'm sceptical about.
According to Islamic teachings, if a fly falls into your food/drink, you need to push it further in so its wings touch your food/drink. It's said that the wings have the antidote property that can prevent food poisoning.
The Prophet said “If a house fly falls in the drink of anyone of you, he should dip it (in the drink), for one of its wings has a disease and the other has the cure for the disease.”
- Source: Sahih Al-Bukhari: Volume 4, Book 54, Number 537
I just heard the claim on the radio (in Malaysia) and many people are calling in to confirm it.