The 8th house corresponds to a water sign and is therefore a house of moksha (self-realization or final liberation).
Life, longevity, death, wills & legacies, insurance benefits, partner's finances, money from partner (including alimony), accidents, long-term illnesses, chronic diseases, disgrace, misfortune, intuition, occult sciences, secret matters, sexual strength, sexual diseases.
The 8th house is a dusthana — an evil or harmful house. It is worse than the 6th and nearly equal in destructiveness to the 12th. Planets in the 8th will suffer, as will the houses they rule. Problems indicated by the 8th are intense and do not improve in time (aspects and sign placements must, however, be considered).
Mrityu bhava is generally thought of as the house of death. This is because it governs the manner and cause of death and because it destroys whatever it comes in contact with. However, the 8th is, in fact, a house of life (along with the 3rd). A good 8th gives long life, a bad 8th short life. A powerful 8th means a person will be energetic and full of life. Notice that in all world champion boxers the most significant aspect of the horoscope is the 8th. Muhammed Ali, who has 5 planets in the 8th, simply could not have the life force knocked out of him, even briefly.
Among other things, this house rules the partner's money. Threrefore it reveals problems arising in marriage over the handling of income. Regarding alimony, it will show what a woman may receive after divorce. As for the ex-husband, if his 8th house is severely afflicted, he will be ordered to pay more than he can afford.
The 8th is also a moksha house, which stirs an interest in moksha or final liberation. More than the other moksha houses (the 4th & 12th), it involves secret or occult knowledge.
The karaka, or indicator, of the 8th is Saturn.
Retrograde 8th lord — lifespan is predetermined. The same effect can be manifested if the owners of the 7th and 2nd houses are retrograde.
Source: «Ancient Hindu Astrology for the Modern Western Astrologer» by James Braha