Sahih Bukhari 7:71:621
The Prophet said, "Fever is from the heat of Hell, so abate fever with water."
See also:Sahih Bukhari 7:71:619, Sahih Bukhari 7:71:620, Sahih Bukhari 7:71:622
Once again, Mohammad never ceases to amaze the world of modern science. After all, it is Allah who ensured the predestination of everyone's actions and sayings - as such, it was Allah, who made sure to give his first and final prophet the ability to come up with such wisdom.
However, what is sad is that Mohammad could have been believed in 7th century Arabia only because their was no ready access to water, and for desert dwellers, water was probably worth its in weight in oil.
But, to have Muslims pass off that every word Mohammad spoke as being divine inspiration, timeless, eternal and wise is utterly negligent bordering reckless.
If that is the case, every Muslim should cure their fever with water. Otherwise, they would be doing Mohammad a disservice by proving him wrong.