‘Kaal Sarp Yog’ is caused when all planets are heamed between rahu and ketu. Normally ‘Kaal Sarp Yog’ is a bad yog where person has sudden fall, troubles and low peace and prosperity even though there are better yog in horoscope. Technically astrology can not be practices in isolation operative Dasha transist etc have to be considered. if dasha of rahu or ketu  has passed in prime time of life or it comes is very old age or in childhood then ‘Kaal Sarp Yog’ bcomes less effective. If dispositors of rahu ketu are in own sign then also bad affect of ‘Kaal Sarp Yog’ is reduced. If rahu ketu aspected, conjoined in Jupiter or Venus star though in that case karkatava of Jupiter and ketu gets adversely affected, is sign of relief.

As per NADI astrology , if planets are heamed between ketu and rahu, means there is no planet between rahu to ketu considering anticlockwise, then ‘Kaal Sarp Yog’ bcomes ‘Kaal Mitra Yog’, because Rahu can not engulf any planet, how ever it has to be considered if planets are caught between rahu to ketu.

‘Kaal Sarp Yog’ though is  bad gives good result if it happens in upachaya sthana like 3, 6, 10, 11. It will do extra ordinary well but will hamper few other bhava equally.

Few granth go in further detail and name ‘Kaal Sarp Yog’ based on asta naga like sesha naag , vaasuki ,  padma etc and suggest remedies accordingly. Naag pratisthapana aslesha bali sarp sahanti and sarp samskaar along with subramanya homa are performed  to pacify effect of ksy