I want to share a Hadith and my personal experience.

The Hadith is that one should wash their feet with cold water after bathing as it protects you from ‘sadaa’

This Hadtih has been shared by Dr. Nazir Hussain several times in his program Tib-e-Nabvi on Health TV and has also been quoted by Dr. Khalid Ghaznavi in his book Tib-e-Nabvi.

Sadaa is interpreted as flu, cold, sore throat, fever, cough and headache.

Dr. Nazir Hussain says that whenever he use to come to Pakistan he got allergies because of the pollution (he used to live in Austria), but since he started following the Hadith, he has been perfectly fine.

He says

"I started following this Hadith lately, and this is the first winter season of my life that I haven’t been taken ill by flu, fever and sore throat. These things were too common for me throughout the winter period, but by the grace of Allah and our beloved Prophet(ﷺ) I have found the solution."