Astronomically speaking, the sixth house is that one-12th sector of the local sky just below the western horizon (see above picture) occupied by planets in the two hours after they set.

The sixth house, like the sixth sign Virgo, represents the last personal stage in development, and is thus a critical one. The self-adjustment we undergo here determines our ability to relate to others on an equal footing (seventh house), and, by its success or failure, unites us with or separates us from others. This is the house of work and health or the lack of either, hygiene and nutrition, service, servants and servitude, daily routine, employment by others, and small animals and pets. Whereas fifth house activities are done for their own sake, sixth house work is done out of necessity or in support of other, more self-expressive activities. When our work becomes an end in itself, however, or we lose track of its purpose, it becomes pointless, and the result can be physical or psychological illness. The issue with planets in the sixth house is to remember what the purpose of our work is, where is it’s joy? Without this knowledge, life isn’t worth living.

This Sixth House of Astrology Houses page and much of this 550-page resource website are taken from You and the Universe.