Work as opposed to career
The tenth house holds the career: the arc, the standing, the title. The sixth holds the job: the tasks, the colleagues, the software, the hours. Someone can have a glittering tenth house and a miserable sixth, which is the chart signature of a prestigious role that is unpleasant to actually perform.
Health as maintenance
Physical health sits here, understood as upkeep rather than fate. Diet, sleep, exercise, the small chronic complaints that respond to routine. Serious illness and surgery are traditionally eighth house matters. Nothing in this house should be read as a diagnosis, and any astrologer who does so is overstepping.
Service and standards
The older name for this house is service, which reads badly now but points at something real: work done for someone else, to their specification, where being right matters more than being interesting. It also covers the standard you apply to yourself, which is why a heavy sixth house so often describes someone competent and quietly dissatisfied.
Planets here
Mercury and the sixth house get on well; the placement usually produces someone good at systems and detail. Mars adds pace and a short fuse about inefficiency. Saturn produces genuine craft and a tendency to overwork. Neptune is the hardest fit, since routine and vagueness pull against each other.
Small animals also live in this house, which sounds arbitrary until you remember that pets are a daily obligation performed without applause.
Opposite the twelfth
Sixth and twelfth face each other as the managed against the unmanageable. One is the checklist; the other is everything that does not fit on it. Charts loaded on the sixth tend to solve problems by tightening the routine, which works until it does not.
The empty house fallacy, which starts here
The sixth is one of the houses people most often find empty, and it produces the most anxious questions. There are twelve houses and ten commonly used bodies, so most charts leave four or five houses with nothing in them. That is arithmetic, not diagnosis.
An empty house is read through the sign on its cusp and the planet ruling that sign. If Sagittarius is on the sixth cusp, Jupiter is the ruler, and wherever Jupiter sits is where your working routine gets decided. A person with an empty sixth and Jupiter in the tenth works in a way shaped almost entirely by their public role, which is a real and specific reading arrived at without a single planet in the house.
Questions people ask about this
Can the sixth house diagnose an illness?
No. It describes habits, routines and upkeep. Reading a medical diagnosis from a chart is not something this site will do.
What is the difference between the sixth and tenth houses?
The sixth is the work itself; the tenth is the standing that work earns you.
Why are pets in the sixth house?
Traditionally the house covers small domestic animals, on the same logic as daily routine: a recurring obligation performed privately.