Caatur Maasya is a four month period from Aashaada Suddha Ekaadasi to Kaartheeka Suddha Ekaadasi. These four months’ period was supposed to be rainy season and early autumn period. During this period, in ancient days, the monks, sages and holy men used to stay put at one place and doing dharma pracaara. Nowadays, they have changed this four months’ period into a four fortnights’ period (Caatur-Paksha). It has been reduced to 48 days only, nowadays, for all practical purposes. The monks observe ‘one place living’ rule from Aashada Krishna Trayodashi to Bhadrapada Sukla Pournami only and they do seemollangana or crossing border on Bhadrapada pournami night. ‘One place living’ was mainly done to prevent harms to rainy season creatures – like insects, worms and reptiles etc.
Dakshinaayana or the period in which the Sun is supposed to move towards tropic of cancer to tropic of capricon is considered as ‘night’ period for Gods and Lord Narayana goes into yogic sleep (yogic nidra) from Aashada Ekadasi (Sayana Ekadasi) to Kaarthika Ekadasi (Uttana Ekadasi). According to the traditions, durng this four month period, one has to refrain from indulging in worldly functions, put concentrate more on spiritual pursuits. That is why, duirng this period, marriage and other functions should not be conducted. So during this period, only vows or vratas have to be observed.
The tonugue is an important organ,which is the root cause for various diseases and disorders. So it has to be tamed and controlled. That is why certain food restrictions are stipulated during these four months, to be strictly observed by all human beings irrespective of caste, creed, community, country and sex etc.
From Aashada suddha Ekadasi to Sraavana Suddha Dasami, one is prohibited from eating vegetables. Vegetables include fruits, raw vegetables, eatable flowers, barks, leaves, roots etc., -the only exception being mango fruit and coconut in certain areas. Even some pulses have to be avoided during this period.
From Sraavana Suddha Ekadasi to Bhadrapada Suddha Dasami, curd and items made out of curd should be avoided. However, watery diluted curd (buttermilk) can be used.
From Bhadrapada Suddha Ekadasi to Aasweena Suddha Dasami, milk and milky items like milk swee etc., have to be avoided. However, coconut milk can be used.
From Aaasweena Suddha Ekadasi to Kaarthika Suddha Dasami, one has to avoid all pulses and many seeded vegetables like pumpkins and ladies fingers. It is called dvidala vrata and bahu beeja vrata. At the end of Kaarthika Chaturdasi, one has to do ‘vana bhojana’ or ‘Datri Havana’ and complete the Chaturmasya vrata with eating all vegetables and pulses etc. This vrata is must for all and good for health. Will power alone is necessary to carry out this vrata.
Apart from these food restrictions, one has to do as many vows as possible and do many religious rites like paarayana of granthas and poojas.