MERCURY IN THE SIXTH HOUSE makes the mentality too active for the person's own good, for he is extremely ambitious and therefore liable to over-tax himself to the detriment of his health, and the disability of the nervous system is most likely to express itself by a digestive disorder in the region governed by Virgo, the sixth sign, viz., the intestines.
Such people are supersensitive to the conditions of others which affects their health bringing much trouble and worry in dealing with servants and subordinates. They are fond of the study of hygiene and diet and meet with considerable success in the practice of the chemistry of foods, particularly if Mercury is well-aspected. Adverse aspects of Saturn to a Sixth House Mercury make a chronic invalid of a most melancholy mind. The adverse aspects of Mars and Uranus are fruitful sources of suicide through brooding over disease.
Max Heindel