The classic Chaas (Chaach/Mattha) also known as the Indian version of buttermilk is a refreshingly cooling summer drink made with creamy yogurt and seasonings.
Buttermilk has a lot of sodium content which is not good for patients with kidney problems. Avoid drinking it if you are one with a kidney ailment. Buttermilk can worsen your cold. It is not advisable to drink buttermilk at night during fever, cold and pollen allergy.