House-6, as 12th-from-7th, shows the loss or dissolution of matters of house-7. Not only is house-6 the container for marital conflict (loss of marriage balance), poverty (loss of business agreements) and debt (loss of financial balance) but very importantly house-6 shows loss of the body's internal balance.
Health is a state of equilibrium. To know health, to be healthy, the physical body must be in a balanced relationship with the astral body & causal body. (Or if you prefer another energy-body model, whatever metaphysical system appeals to you, the various energy bodies must be in harmonious balance to enjoy health.)
Within the physical body itself, are a variety of exceptionally complex internal systems - pumps, pipes, membranes, networks - which must all cooperate and support each other. If one internal system weakens, the rest receive extra stress and the long-term imbalance becomes unsustainable.
So, disease is the result of loss of balance. The seventh house will indicate your natural state of balance. Strong planets in house-6 show past-life karma that unconsciously but compulsively detracts from your state of balance. By studying the relationship between your 6th & 7th radix houses, it is possible to see where the psychic imbalances are, where the harmony gets drained off by internal conflict. If house-6 is clear, yet the 7th house is troubled, there may be work to do in your marriage & partnerships.
But very predominantly the serious health challenges - which most of us face at some time in our lives - originate in house-6, with the radix-6th-lord, and various drishti upon the lord & His house.Navamsha role of L-6 which shows the subconscious attitude toward imbalances, the D-30 Trimshamsha showing hidden expectations of "misfortune", and even the natural marakas Shani, Kuja, & Rahu can all contribute to the stress, frustration, and often despair that a serious accident or disease may cause.
In cases of poverty, marital conflict, and disease - the major "victim state" imbalances - our discovery focuses on L-6 and His home Ripu Bhava, house of "loss of balance".