It is a very effective and powerful Yagya like Mahamrityunjaya Yagya. It is based upon some very powerful and special Mantra of Maharishi Bhrigu ( father of shukra / venus and son of lord Brahma). Bhrigu Samhita is a famous astrological text of 5000 years old.According to Purana- Maharishi Bhrigu was devolped the Sanjeevani Mantra under the guidance of lord Shiva which is very powerful and success to give the life to dead bodies and Acharya Sukra made the application of this great science by experimenting it on the dead bodies of demons in the battle field & he made dead demons again lived one.
Lot of research have been done on this great science Sanjeevani Vidya. So Bhrigu Maha Yagya is a very powerful Yagya which is performed by some specially trained Vedic Pandits. These kind of Yagyas are rare now a days. It gives the life and increase life span. Specially if a person is in great danger, fighting with life and death,to avoid the fatal situation and in a critical health condition should be done. Also good to have this Yagya once in a life time to insured the life and avoid great dangers. Bhrigu Maha Yagya and Mahamrityunjay Yagya both are very special Yagya, but Bhrigu Maha Yagya is more powerful and effective if done in proper procedure and system. 21 / 51 or 101 Vedic Pandits perform it for 2 to 3 weeks (as per the category, it is a Yagya package combination of some other Yagyas)
This Yagya is an expensive one, because it takes long time and lot of things required for offering.