Pratyavarohana ritual was performed in ancient times in the month of Margashirsha, also known as Agrahayana. The word pratyavarohana means descending again. It is believed that in ancient times people used to sleep very high above the ground on a high cot to avoid snake bites. They used to sleep high above the ground starting from Shravan month (July – August) – the start of monsoon season. People used to come to sleep on the ground only in Margashirsha month. The sleeping on the ground again was known as pratyavarohana ritual.
Prayers and mantras dedicated to snakes asking them not to harm the family were chanted on the occasion. Offerings like sweets made of milk were offered to snakes. The houses were plastered again or repainted on the occasion.
The ritual was performed on the full moon day in the month or on the first day of the month.
As per some scholars the ritual was performed at the beginning of each season.